<PAGE>

            As filed with the Securities and Exchange Commission on May 25, 2006
                                                 Registration No. 333-__________

================================================================================

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                   ----------

                                    FORM S-8

                             REGISTRATION STATEMENT
                        UNDER THE SECURITIES ACT OF 1933

                                   ----------

                           ENZON PHARMACEUTICALS, INC.
             (Exact name of Registrant as specified in its charter)

<TABLE>
<S>                                                          <C>
            DELAWARE                                              22-2372868
(State or other jurisdiction of                                (I.R.S. Employer
 incorporation or organization)                              Identification No.)
</TABLE>

                                685 ROUTE 202/206
                          BRIDGEWATER, NEW JERSEY 08807
                    (Address of principal executive offices)

                                   ----------

              ENZON PHARMACEUTICALS, INC. 2001 INCENTIVE STOCK PLAN
                            (Full title of the plan)

                                   ----------

                              JEFFREY H. BUCHALTER
                             CHIEF EXECUTIVE OFFICER
                           ENZON PHARMACEUTICALS, INC.
                                685 ROUTE 202/206
                          BRIDGEWATER, NEW JERSEY 08807
                     (Name and address of agent for service)

                                 (908) 541-8600
          (Telephone number, including area code, of agent for service)

                                   ----------

                                   Copies to:

Scott Waldman, Esq.                      Kevin T. Collins, Esq.
Director and Associate General Counsel   Heller Ehrman LLP
Enzon Pharmaceuticals, Inc.              Times Square Tower
685 Route 202/206                        7 Times Square
Bridgewater, New Jersey 08807            New York, New York 10036
Telephone - (908) 541-8600               Telephone - (212) 832-8300

                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
                                                                                                             Amount of
Title of each class of securities   Amount to be         Proposed maximum           Proposed maximum       registration
         to be registered            registered      offering price per share   aggregate offering price        fee
---------------------------------   ------------     ------------------------   ------------------------   ------------
<S>                                 <C>              <C>                        <C>                        <C>
Common Stock, $0.01 par value per
share (1)........................     4,000,000 (2)          $7.24 (3)                 $28,960,000           $3,098.72
</TABLE>

----------
(1)  One preferred stock purchase right will attach to and trade with each share
     of common stock sold in the offering. These rights are also covered by this
     registration statement and the value attributable to them, if any, is
     reflected in the market price of the common stock.

(2)  This Registration Statement covers the additional 4,000,000 shares of
     common stock approved by the stockholders of Enzon Pharmaceuticals, Inc. on
     May 18, 2006, that are issuable pursuant to Enzon Pharmaceuticals, Inc.'s
     2001 Incentive Stock Plan, plus an indeterminate number of additional
     shares which may be offered and issued to prevent dilution resulting from
     stock splits, stock dividends or similar transactions.

(3)  Estimated solely for the purpose of calculating the registration fee in
     accordance with Rule 457(h) and Rule 457(c) under the Securities Act of
     1933, as amended, based upon the average of the high and low prices of the
     registrant's Common Stock on the Nasdaq National Market on May 23, 2006.

================================================================================

<PAGE>

                                     PART I
               INFORMATION REQUIRED IN THE SECTION 10(A)PROSPECTUS

ITEM 1. PLAN INFORMATION.*

ITEM 2. REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION.*

*    Information required by Part I to be contained in the Section 10(a)
     prospectus is omitted from this registration statement in accordance with
     Rule 428 under the Securities Act and the Note to Part I of Form S-8.

                                     PART II
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3. INCORPORATION OF DOCUMENTS BY REFERENCE.

     The following documents filed with the Securities and Exchange Commission
(the "Commission") are hereby incorporated by reference:

     (a) The registrant's Transition Report on Form 10-K for the transition
period ended December 31, 2005, filed with the Commission on March 3, 2006,
pursuant to Section 13(a) of the Securities Exchange Act of 1934, as amended
(the "Exchange Act").

     (b) All other reports filed pursuant to Section 13(a) or 15(d) of the
Exchange Act since the end of the fiscal period covered by the Transition Report
referred to in (a) above.

     (c) The description of the Company's Common Stock, par value $.01 per
share, as contained in a registration statement on Form 8-A filed on October 29,
1984, as amended by Form 8-A/A filed on October 15, 1990, including any
amendment or report filed for the purpose of updating such description.

     (d) The description of the Company's Series B Preferred Stock Purchase
Rights as contained in a registration statement on Form 8-A filed on May 22,
2002, including any amendment or report filed for the purpose of updating such
description.

     All documents subsequently filed by the registrant pursuant to Sections
13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing of a
post-effective amendment which indicates that all securities offered hereby have
been sold or which deregisters all securities then remaining unsold, shall be
deemed to be incorporated by reference in this registration statement and to be
part hereof from the date of filing such documents.

ITEM 4. DESCRIPTION OF SECURITIES.

     Not applicable.

ITEM 5. INTERESTS OF NAMED EXPERTS AND COUNSEL.

     Not applicable.

ITEM 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

     Section 145 of the Delaware General Corporation Law (the "DGCL") empowers a
corporation to indemnify any person who was or is a party or is threatened to be
made a party to any threatened, pending or completed action, suit or proceeding,
whether civil, criminal, administrative or investigative (other than an action
by or in the right of the corporation) by reason of the fact that he or she is
or was a director, officer, employee or agent of the corporation or is or was
serving at the request of the corporation as a director, officer, employee or
agent of another corporation


                                        1

<PAGE>

or other enterprise, against expenses (including attorneys' fees), judgments,
fines and amounts paid in settlement actually and reasonably incurred by him or
her in connection with such action, suit or proceeding if he or she acted in
good faith and in a manner he or she reasonably believed to be in, or not
opposed to, the best interests of the corporation, and, with respect to any
criminal action or proceeding, had no reasonable cause to believe his or her
conduct was unlawful.

     Section 145 also empowers a corporation to indemnify any person who was or
is a party or is threatened to be made a party to any threatened, pending or
completed action or suit by or in the right of the corporation to procure a
judgment in its favor by reason of the fact that such person acted in any of the
capacities set forth above, against expenses (including attorneys' fees)
actually and reasonably incurred by him or her in connection with the defense or
settlement of such action or suit if he or she acted under similar standards,
except that no indemnification may be made in respect of any claim, issue or
matter as to which such person shall have been adjudged to be liable to the
corporation unless, and only to the extent that, the Delaware Court of Chancery
or the court in which such action was brought shall determine that despite the
adjudication of liability such person is fairly and reasonably entitled to
indemnity, for such expenses which the Delaware Court of Chancery or such other
court shall deem proper.

     Section 145 further provides that to the extent a director, officer,
employee or agent of a corporation has been successful in the defense of any
action, suit or proceeding referred to above or in the defense of any claim,
issue or matter therein, he or she shall be indemnified against expenses
(including attorneys' fees) actually and reasonably incurred by him or her in
connection therewith, that indemnification provided for by Section 145 shall not
be deemed exclusive of any other rights to which the indemnified party may be
entitled; and that the corporation is empowered to purchase and maintain
insurance on behalf of any person who is or was a director, officer, employee or
agent of the corporation against any liability asserted against him or her in
any such capacity or arising out of his or her status as such, whether or not
the corporation would have the power to indemnify him or her against such
liability under Section 145.

     Section 102(b)(7) of the DGCL enables a corporation in its certificate of
incorporation to limit the personal liability of members of its board of
directors for violation of a director's fiduciary duty of care. Article 10 of
the Company's certificate of incorporation, as authorized by Section 102(b)(7),
provides that a director shall not be liable to the Company for breach of a
fiduciary duty, except for liability:

     -    for any breach of the director's duty of loyalty to the Company or the
          Company's stockholders;

     -    for acts or omissions not in good faith or which involve intentional
          misconduct or a knowing violation of law;

     -    under section 174 of the DGCL providing for liability of directors for
          unlawful payment of dividends or unlawful stock purchases or
          redemptions;

     -    for any transaction from which a director derived an improper benefit;
          or

     -    for any act or omission occurring prior to the date when Article 10
          became effective.

     Section 8.1 of the Company's bylaws provides for the indemnification, to
the fullest extent authorized by law, of any person made, or threatened to be
made, a party to an action or proceeding, whether criminal, civil,
administrative or investigative, against expenses, judgments, fines, and amounts
paid in settlement incurred in connection with such action or proceeding, by
reason of the fact that such person is or was a director or officer of the
Company. The Company's Directors' and Officers' Liability Insurance, which is
provided for under Section 8.3 of the Company's bylaws, insures directors and
officers against any liability arising out of such person's status as a director
or officer, and insures the Company against its obligations to indemnify its
directors and officers.

     Certain of the Company's officers and directors have executed indemnity
agreements which supplement the protections provided by the Company's
certificate of incorporation and bylaws. These agreements require the Company to
pay for any damages, judgments, settlements, costs and expenses for the defense
of legal actions,


                                        2

<PAGE>

claims, proceedings and appeals due to any actual or alleged breach of duty,
neglect, error, misstatement, misleading statement, omission or other act done,
suffered or wrongfully attempted by the officer or director. If the Company does
not pay such costs and expenses within 90 days after it receives a written
claim, such officers or directors may bring a suit against the Company to
recover the unpaid amount of the claim. If such officer or director is
successful, the Company will be required to pay for the expenses incurred
relating to the claim.

Item 7. EXEMPTION FROM REGISTRATION CLAIMED. Not applicable.

Item 8. EXHIBITS.

<TABLE>
<CAPTION>
Exhibit
 Number
-------
<S>       <C>
  4.1     Rights Agreement dated as of May 17, 2002 ("Rights Agreement") between the
          Company and Continental Stock Transfer & Trust Company, as Rights Agent
          (incorporated by reference to exhibit 4.2 to the Company's Form 8-A (File No.
          000-12957) filed with the Commission on May 22, 2002).
  5.1     Opinion of Heller Ehrman LLP.
  23.1    Consent of Heller Ehrman LLP (included in Exhibit 5.1).
  23.2    Consent of Independent Registered Public Accounting Firm.
  24.1    Powers of Attorney (included in signature page to this registration statement).
</TABLE>

Item 9. UNDERTAKINGS.

     (a) The undersigned registrant hereby undertakes:

          (1) To file, during any period in which offers or sales are being
made, a post-effective amendment to this registration statement:

               (i) To include any prospectus required by Section 10(a)(3) of the
Securities Act;

               (ii) To reflect in the prospectus any facts or events arising
after the effective date of the registration statement (or the most recent
post-effective amendment thereof) which, individually or in the aggregate,
represent a fundamental change in the information set forth in the registration
statement. Notwithstanding the foregoing, any increase or decrease in volume of
securities offered (if the total dollar value of securities offered would not
exceed that which was registered) and any deviation from the low or high end of
the estimated maximum offering range may be reflected in the form of prospectus
filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the
changes in volume and price represent no more than a 20% change in the maximum
aggregate offering price set forth in the "Calculation of Registration Fee"
table in the effective registration statement; and

               (iii) To include any material information with respect to the
plan of distribution not previously disclosed in the registration statement or
any material change to such information in the registration statement;

     Provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) above do not
apply if the information required to be included in a post-effective amendment
by those paragraphs is contained in periodic reports filed with or furnished to
the Commission by the registrant pursuant to Section 13 or Section 15(d) of the
Exchange Act that are incorporated by reference in the registration statement.


                                        3

<PAGE>

          (2) That, for the purpose of determining any liability under the
Securities Act, each such post-effective amendment shall be deemed to be a new
registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

          (3) To remove from registration by means of a post-effective amendment
any of the securities being registered which remain unsold at the termination of
the offering.

     (b) The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act, each filing of the
registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Exchange Act (and, where applicable, each filing of an employee benefit plan's
annual report pursuant to Section 15(d) of the Exchange Act) that is
incorporated by reference in the registration statement shall be deemed to be a
new registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

     (c) Insofar as the indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers and controlling persons
of the registrant pursuant to the foregoing provisions, or otherwise, the
registrant has been advised that in the opinion of the Commission such
indemnification is against public policy as expressed in the Securities Act and
is, therefore, unenforceable. In the event that a claim for indemnification
against such liabilities (other than the payment by the registrant of expenses
incurred or paid by a director, officer or controlling person of the registrant
in a successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered hereunder, the registrant will, unless in the opinion of its counsel
the matter has been settled by controlling precedent, submit to a court of
appropriate jurisdiction the question of whether such indemnification by it is
against public policy as expressed in the Securities Act and will be governed by
the final adjudication of such issue.

                            [Signature Pages Follow]


                                        4

<PAGE>

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Bridgewater, State of New Jersey, on May 25, 2006.

                                  Enzon Pharmaceuticals, Inc.


                                  By: /s/ Jeffrey H. Buchalter
                                      ------------------------------------------
                                      Jeffrey H. Buchalter
                                      President, Chief Executive Officer and
                                      Chairman of the Board (Principal Executive
                                      Officer)

                                POWER OF ATTORNEY

     KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Jeffrey H. Buchalter and Craig A. Tooman,
jointly and severally, his or her attorneys-in-fact and agents, each with the
power of substitution and resubstitution, for him or her and in his or her name,
place or stead, in any and all capacities, to sign any amendments to this
Registration Statement on Form S-8, and to file such amendments, together with
exhibits and other documents in connection therewith, with the Securities and
Exchange Commission, granting to each attorney-in-fact and agent, full power and
authority to do and perform each and every act and thing requisite and necessary
to be done in and about the premises, as fully as he or she might or could do in
person, and ratifying and confirming all that the attorneys-in-fact and agents,
or his or her substitute or substitutes, may do or cause to be done by virtue
hereof.

     Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.

<TABLE>
<CAPTION>
            Signature                                    Title                            Date
            ---------                                    -----                            ----
<S>                                 <C>                                               <C>


/s/ Craig A. Tooman                 Executive Vice President, Finance and Chief       May 25, 2006
---------------------------------   Financial Officer (Principal Financial
Craig A. Tooman                     Officer)


/s/ Jeffrey H. Buchalter            President, Chief Executive Officer and Chairman   May 25, 2006
---------------------------------   of the Board (Principal Executive Officer)
Jeffrey H. Buchalter


                                    Director
---------------------------------
Goran Ando


/s/ Rolf A. Classon                 Director                                          May 25, 2006
---------------------------------
Rolf A. Classon


/s/ Robert LeBuhn                   Director                                          May 25, 2006
---------------------------------
Robert LeBuhn


                                    Director
---------------------------------
Victor P. Micati


/s/ Phillip M. Renfro               Director                                          May 25, 2006
---------------------------------
Phillip M. Renfro


                                    Director
---------------------------------
Robert C. Salisbury
</TABLE>


                                        5

<PAGE>

                                INDEX TO EXHIBITS

<TABLE>
<CAPTION>
Exhibit
 Number
-------
<S>       <C>
  5.1     Opinion of Heller Ehrman LLP.
  23.1    Consent of Heller Ehrman LLP (included in Exhibit 5.1).
  23.2    Consent of Independent Registered Public Accounting Firm.
  24.1    Powers of Attorney (included in signature page to this registration statement).
</TABLE>
[{"type": "S-8", "sequence": "1", "filename": "y21734sv8.txt", "description": "FORM S-8", "secsgml_size_bytes": 21635}]
{"company-data": {"conformed-name": "ENZON PHARMACEUTICALS INC", "cik": "0000727510", "assigned-sic": "2836", "irs-number": "222372868", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-134453", "film-number": "06866878"}, "business-address": {"street1": "685 ROUTE 202/206", "city": "BRIDGEWATER", "state": "NJ", "zip": "08807", "phone": "908 541 8711"}, "mail-address": {"street1": "685 ROUTE 202/206", "street2": "ATT:  GENERAL COUNSEL", "city": "BRIDGEWATER", "state": "NJ", "zip": "08807"}, "former-company": [{"former-conformed-name": "ENZON PHARMACEUTICALS  INC", "date-changed": "20021211"}, {"former-conformed-name": "ENZON PHARMACEUTICAL  INC", "date-changed": "20021210"}, {"former-conformed-name": "ENZON INC", "date-changed": "19920703"}]}
As filed with the Securities and Exchange Commission on May 25, 2006
                                                 Registration No. 333-__________

================================================================================

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                   ----------

                                    FORM S-8

                             REGISTRATION STATEMENT
                        UNDER THE SECURITIES ACT OF 1933

                                   ----------

                           ENZON PHARMACEUTICALS, INC.
             (Exact name of Registrant as specified in its charter)
DELAWARE                                              22-2372868
(State or other jurisdiction of                                (I.R.S. Employer
 incorporation or organization)                              Identification No.)
685 ROUTE 202/206
                          BRIDGEWATER, NEW JERSEY 08807
                    (Address of principal executive offices)

                                   ----------

              ENZON PHARMACEUTICALS, INC. 2001 INCENTIVE STOCK PLAN
                            (Full title of the plan)

                                   ----------

                              JEFFREY H. BUCHALTER
                             CHIEF EXECUTIVE OFFICER
                           ENZON PHARMACEUTICALS, INC.
                                685 ROUTE 202/206
                          BRIDGEWATER, NEW JERSEY 08807
                     (Name and address of agent for service)

                                 (908) 541-8600
          (Telephone number, including area code, of agent for service)

                                   ----------

                                   Copies to:

Scott Waldman, Esq.                      Kevin T. Collins, Esq.
Director and Associate General Counsel   Heller Ehrman LLP
Enzon Pharmaceuticals, Inc.              Times Square Tower
685 Route 202/206                        7 Times Square
Bridgewater, New Jersey 08807            New York, New York 10036
Telephone - (908) 541-8600               Telephone - (212) 832-8300

                         CALCULATION OF REGISTRATION FEE
Amount of
Title of each class of securities   Amount to be         Proposed maximum           Proposed maximum       registration
         to be registered            registered      offering price per share   aggregate offering price        fee
---------------------------------   ------------     ------------------------   ------------------------   ------------
Common Stock, $0.01 par value per
share (1)........................     4,000,000 (2)          $7.24 (3)                 $28,960,000           $3,098.72
----------
(1)  One preferred stock purchase right will attach to and trade with each share
     of common stock sold in the offering. These rights are also covered by this
     registration statement and the value attributable to them, if any, is
     reflected in the market price of the common stock.

(2)  This Registration Statement covers the additional 4,000,000 shares of
     common stock approved by the stockholders of Enzon Pharmaceuticals, Inc. on
     May 18, 2006, that are issuable pursuant to Enzon Pharmaceuticals, Inc.'s
     2001 Incentive Stock Plan, plus an indeterminate number of additional
     shares which may be offered and issued to prevent dilution resulting from
     stock splits, stock dividends or similar transactions.

(3)  Estimated solely for the purpose of calculating the registration fee in
     accordance with Rule 457(h) and Rule 457(c) under the Securities Act of
     1933, as amended, based upon the average of the high and low prices of the
     registrant's Common Stock on the Nasdaq National Market on May 23, 2006.

================================================================================
PART I
               INFORMATION REQUIRED IN THE SECTION 10(A)PROSPECTUS

ITEM 1. PLAN INFORMATION.*

ITEM 2. REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION.*

*    Information required by Part I to be contained in the Section 10(a)
     prospectus is omitted from this registration statement in accordance with
     Rule 428 under the Securities Act and the Note to Part I of Form S-8.

                                     PART II
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3. INCORPORATION OF DOCUMENTS BY REFERENCE.

     The following documents filed with the Securities and Exchange Commission
(the "Commission") are hereby incorporated by reference:

     (a) The registrant's Transition Report on Form 10-K for the transition
period ended December 31, 2005, filed with the Commission on March 3, 2006,
pursuant to Section 13(a) of the Securities Exchange Act of 1934, as amended
(the "Exchange Act").

     (b) All other reports filed pursuant to Section 13(a) or 15(d) of the
Exchange Act since the end of the fiscal period covered by the Transition Report
referred to in (a) above.

     (c) The description of the Company's Common Stock, par value $.01 per
share, as contained in a registration statement on Form 8-A filed on October 29,
1984, as amended by Form 8-A/A filed on October 15, 1990, including any
amendment or report filed for the purpose of updating such description.

     (d) The description of the Company's Series B Preferred Stock Purchase
Rights as contained in a registration statement on Form 8-A filed on May 22,
2002, including any amendment or report filed for the purpose of updating such
description.

     All documents subsequently filed by the registrant pursuant to Sections
13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing of a
post-effective amendment which indicates that all securities offered hereby have
been sold or which deregisters all securities then remaining unsold, shall be
deemed to be incorporated by reference in this registration statement and to be
part hereof from the date of filing such documents.

ITEM 4. DESCRIPTION OF SECURITIES.

     Not applicable.

ITEM 5. INTERESTS OF NAMED EXPERTS AND COUNSEL.

     Not applicable.

ITEM 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

     Section 145 of the Delaware General Corporation Law (the "DGCL") empowers a
corporation to indemnify any person who was or is a party or is threatened to be
made a party to any threatened, pending or completed action, suit or proceeding,
whether civil, criminal, administrative or investigative (other than an action
by or in the right of the corporation) by reason of the fact that he or she is
or was a director, officer, employee or agent of the corporation or is or was
serving at the request of the corporation as a director, officer, employee or
agent of another corporation

                                        1
or other enterprise, against expenses (including attorneys' fees), judgments,
fines and amounts paid in settlement actually and reasonably incurred by him or
her in connection with such action, suit or proceeding if he or she acted in
good faith and in a manner he or she reasonably believed to be in, or not
opposed to, the best interests of the corporation, and, with respect to any
criminal action or proceeding, had no reasonable cause to believe his or her
conduct was unlawful.

     Section 145 also empowers a corporation to indemnify any person who was or
is a party or is threatened to be made a party to any threatened, pending or
completed action or suit by or in the right of the corporation to procure a
judgment in its favor by reason of the fact that such person acted in any of the
capacities set forth above, against expenses (including attorneys' fees)
actually and reasonably incurred by him or her in connection with the defense or
settlement of such action or suit if he or she acted under similar standards,
except that no indemnification may be made in respect of any claim, issue or
matter as to which such person shall have been adjudged to be liable to the
corporation unless, and only to the extent that, the Delaware Court of Chancery
or the court in which such action was brought shall determine that despite the
adjudication of liability such person is fairly and reasonably entitled to
indemnity, for such expenses which the Delaware Court of Chancery or such other
court shall deem proper.

     Section 145 further provides that to the extent a director, officer,
employee or agent of a corporation has been successful in the defense of any
action, suit or proceeding referred to above or in the defense of any claim,
issue or matter therein, he or she shall be indemnified against expenses
(including attorneys' fees) actually and reasonably incurred by him or her in
connection therewith, that indemnification provided for by Section 145 shall not
be deemed exclusive of any other rights to which the indemnified party may be
entitled; and that the corporation is empowered to purchase and maintain
insurance on behalf of any person who is or was a director, officer, employee or
agent of the corporation against any liability asserted against him or her in
any such capacity or arising out of his or her status as such, whether or not
the corporation would have the power to indemnify him or her against such
liability under Section 145.

     Section 102(b)(7) of the DGCL enables a corporation in its certificate of
incorporation to limit the personal liability of members of its board of
directors for violation of a director's fiduciary duty of care. Article 10 of
the Company's certificate of incorporation, as authorized by Section 102(b)(7),
provides that a director shall not be liable to the Company for breach of a
fiduciary duty, except for liability:

     -    for any breach of the director's duty of loyalty to the Company or the
          Company's stockholders;

     -    for acts or omissions not in good faith or which involve intentional
          misconduct or a knowing violation of law;

     -    under section 174 of the DGCL providing for liability of directors for
          unlawful payment of dividends or unlawful stock purchases or
          redemptions;

     -    for any transaction from which a director derived an improper benefit;
          or

     -    for any act or omission occurring prior to the date when Article 10
          became effective.

     Section 8.1 of the Company's bylaws provides for the indemnification, to
the fullest extent authorized by law, of any person made, or threatened to be
made, a party to an action or proceeding, whether criminal, civil,
administrative or investigative, against expenses, judgments, fines, and amounts
paid in settlement incurred in connection with such action or proceeding, by
reason of the fact that such person is or was a director or officer of the
Company. The Company's Directors' and Officers' Liability Insurance, which is
provided for under Section 8.3 of the Company's bylaws, insures directors and
officers against any liability arising out of such person's status as a director
or officer, and insures the Company against its obligations to indemnify its
directors and officers.

     Certain of the Company's officers and directors have executed indemnity
agreements which supplement the protections provided by the Company's
certificate of incorporation and bylaws. These agreements require the Company to
pay for any damages, judgments, settlements, costs and expenses for the defense
of legal actions,

                                        2
claims, proceedings and appeals due to any actual or alleged breach of duty,
neglect, error, misstatement, misleading statement, omission or other act done,
suffered or wrongfully attempted by the officer or director. If the Company does
not pay such costs and expenses within 90 days after it receives a written
claim, such officers or directors may bring a suit against the Company to
recover the unpaid amount of the claim. If such officer or director is
successful, the Company will be required to pay for the expenses incurred
relating to the claim.

Item 7. EXEMPTION FROM REGISTRATION CLAIMED. Not applicable.

Item 8. EXHIBITS.
Exhibit
 Number
-------
4.1     Rights Agreement dated as of May 17, 2002 ("Rights Agreement") between the
          Company and Continental Stock Transfer & Trust Company, as Rights Agent
          (incorporated by reference to exhibit 4.2 to the Company's Form 8-A (File No.
          000-12957) filed with the Commission on May 22, 2002).
  5.1     Opinion of Heller Ehrman LLP.
  23.1    Consent of Heller Ehrman LLP (included in Exhibit 5.1).
  23.2    Consent of Independent Registered Public Accounting Firm.
  24.1    Powers of Attorney (included in signature page to this registration statement).
Item 9. UNDERTAKINGS.

     (a) The undersigned registrant hereby undertakes:

          (1) To file, during any period in which offers or sales are being
made, a post-effective amendment to this registration statement:

               (i) To include any prospectus required by Section 10(a)(3) of the
Securities Act;

               (ii) To reflect in the prospectus any facts or events arising
after the effective date of the registration statement (or the most recent
post-effective amendment thereof) which, individually or in the aggregate,
represent a fundamental change in the information set forth in the registration
statement. Notwithstanding the foregoing, any increase or decrease in volume of
securities offered (if the total dollar value of securities offered would not
exceed that which was registered) and any deviation from the low or high end of
the estimated maximum offering range may be reflected in the form of prospectus
filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the
changes in volume and price represent no more than a 20% change in the maximum
aggregate offering price set forth in the "Calculation of Registration Fee"
table in the effective registration statement; and

               (iii) To include any material information with respect to the
plan of distribution not previously disclosed in the registration statement or
any material change to such information in the registration statement;

     Provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) above do not
apply if the information required to be included in a post-effective amendment
by those paragraphs is contained in periodic reports filed with or furnished to
the Commission by the registrant pursuant to Section 13 or Section 15(d) of the
Exchange Act that are incorporated by reference in the registration statement.

                                        3
(2) That, for the purpose of determining any liability under the
Securities Act, each such post-effective amendment shall be deemed to be a new
registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

          (3) To remove from registration by means of a post-effective amendment
any of the securities being registered which remain unsold at the termination of
the offering.

     (b) The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act, each filing of the
registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Exchange Act (and, where applicable, each filing of an employee benefit plan's
annual report pursuant to Section 15(d) of the Exchange Act) that is
incorporated by reference in the registration statement shall be deemed to be a
new registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

     (c) Insofar as the indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers and controlling persons
of the registrant pursuant to the foregoing provisions, or otherwise, the
registrant has been advised that in the opinion of the Commission such
indemnification is against public policy as expressed in the Securities Act and
is, therefore, unenforceable. In the event that a claim for indemnification
against such liabilities (other than the payment by the registrant of expenses
incurred or paid by a director, officer or controlling person of the registrant
in a successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered hereunder, the registrant will, unless in the opinion of its counsel
the matter has been settled by controlling precedent, submit to a court of
appropriate jurisdiction the question of whether such indemnification by it is
against public policy as expressed in the Securities Act and will be governed by
the final adjudication of such issue.

                            [Signature Pages Follow]

                                        4
SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Bridgewater, State of New Jersey, on May 25, 2006.

                                  Enzon Pharmaceuticals, Inc.

                                  By: /s/ Jeffrey H. Buchalter
                                      ------------------------------------------
                                      Jeffrey H. Buchalter
                                      President, Chief Executive Officer and
                                      Chairman of the Board (Principal Executive
                                      Officer)

                                POWER OF ATTORNEY

     KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Jeffrey H. Buchalter and Craig A. Tooman,
jointly and severally, his or her attorneys-in-fact and agents, each with the
power of substitution and resubstitution, for him or her and in his or her name,
place or stead, in any and all capacities, to sign any amendments to this
Registration Statement on Form S-8, and to file such amendments, together with
exhibits and other documents in connection therewith, with the Securities and
Exchange Commission, granting to each attorney-in-fact and agent, full power and
authority to do and perform each and every act and thing requisite and necessary
to be done in and about the premises, as fully as he or she might or could do in
person, and ratifying and confirming all that the attorneys-in-fact and agents,
or his or her substitute or substitutes, may do or cause to be done by virtue
hereof.

     Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.
Signature                                    Title                            Date
            ---------                                    -----                            ----
/s/ Craig A. Tooman                 Executive Vice President, Finance and Chief       May 25, 2006
---------------------------------   Financial Officer (Principal Financial
Craig A. Tooman                     Officer)

/s/ Jeffrey H. Buchalter            President, Chief Executive Officer and Chairman   May 25, 2006
---------------------------------   of the Board (Principal Executive Officer)
Jeffrey H. Buchalter

                                    Director
---------------------------------
Goran Ando

/s/ Rolf A. Classon                 Director                                          May 25, 2006
---------------------------------
Rolf A. Classon

/s/ Robert LeBuhn                   Director                                          May 25, 2006
---------------------------------
Robert LeBuhn

                                    Director
---------------------------------
Victor P. Micati

/s/ Phillip M. Renfro               Director                                          May 25, 2006
---------------------------------
Phillip M. Renfro

                                    Director
---------------------------------
Robert C. Salisbury
5
INDEX TO EXHIBITS
Exhibit
 Number
-------
5.1     Opinion of Heller Ehrman LLP.
  23.1    Consent of Heller Ehrman LLP (included in Exhibit 5.1).
  23.2    Consent of Independent Registered Public Accounting Firm.
  24.1    Powers of Attorney (included in signature page to this registration statement).