<PAGE>

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D. C. 20549
                           --------------------------

                                    FORM 8-K

                                 CURRENT REPORT

                       Pursuant to Section 13 or 15(d) of
                       The Securities Exchange Act of 1934
                            -------------------------

         Date of Report (Date of earliest event reported): April 3, 2006

                          MERRILL LYNCH DEPOSITOR, INC.
                 (ON BEHALF OF PREFERREDPLUS TRUST SERIES CZN-1)
             (Exact name of registrant as specified in its charter)

     DELAWARE                      001-16669                     13-3891329
 (State or other                 (Commission                 (I. R. S. Employer
 jurisdiction  of                 File Number)               Identification No.)
  incorporation)

        WORLD FINANCIAL CENTER,                                     10080
          NEW YORK, NEW YORK                                     (Zip Code)
         (Address of principal
          executive offices)
                           --------------------------

       Registrant's telephone number, including area code: (212) 449-1000

                      INFORMATION TO BE INCLUDED IN REPORT



Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions (see General Instruction A.2.):

[  ]  Written communications pursuant to Rule 425 under the Securities Act
      (17 CFR 230.425)

[  ]  Soliciting material pursuant to Rule 14a-12 under the Exchange Act
      (17 CFR 240.14a-12)

[  ]  Pre-commencement communications pursuant to Rule 14d-2(b) under the
      Exchange Act (17 CFR 240.14d-2(b))

[  ]  Pre-commencement communications pursuant to Rule 13e-4(c) under the
      Exchange Act (17 CFR 240.13e-4(c))

<PAGE>

SECTION 1.        REGISTRANT'S BUSINESS AND OPERATIONS

                  Not applicable.

SECTION 2.        FINANCIAL INFORMATION

                  Not applicable.

SECTION 3.        SECURITIES AND TRADING MARKETS

                  Not applicable.

SECTION 4.        MATTERS RELATED TO ACCOUNTANTS AND FINANCIAL STATEMENTS

                  Not applicable.

SECTION 5.        CORPORATE GOVERNANCE AND MANAGEMENT

                  Not applicable.

SECTION 6.        ASSET-BACKED SECURITIES

                  Not applicable.

SECTION 7.        REGULATION FD

                  Not applicable.

SECTION 8.        OTHER EVENTS

         ITEM 8.01         OTHER EVENTS

                           99.1     Distribution to holders of the PreferredPLUS
                                    Trust Certificates Series CZN-1 on
                                    April 3, 2006.

                                    For information with respect to the
                           underlying securities held by PreferredPLUS Trust
                           Series CZN-1, please refer to Citizens Communications
                           Company's (Commission file number 001-11001) periodic
                           reports, including annual reports on Form 10-K,
                           quarterly reports on Form 10-Q and current reports on
                           Form 8-K, and other information on file with the
                           Securities and Exchange Commission (the "SEC"). You
                           can read and copy these reports and other information
                           at the public reference facilities maintained by the
                           SEC at Room 1580, 100 F Street, NE, Washington, D.C.
                           20549. You may obtain copies of this material for a
                           fee by writing to the SEC's Public Reference Section
                           of the SEC at 100 F Street, NE, Washington, D.C.
                           20549. You may obtain information about the operation
                           of the Public Reference Room by calling the SEC at
                           1-800-SEC-0330. You can also access some of this
                           information electronically by means of the SEC's
                           website on the Internet at http://www.sec.gov, which
                           contains reports, proxy and information statements
                           and other information that the underlying securities
                           issuer has filed electronically with the SEC.
<PAGE>

                                            Although we have no reason to
                           believe the information concerning the underlying
                           securities or the underlying securities issuer
                           contained in the underlying securities issuer's
                           Exchange Act reports is not reliable, neither the
                           depositor nor the trustee participated in the
                           preparation of such documents or made any due
                           diligence inquiry with respect to the information
                           provided therein. No investigation with respect to
                           the underlying securities issuer (including, without
                           limitation, no investigation as to its financial
                           condition or creditworthiness) or of the underlying
                           securities has been made. You should obtain and
                           evaluate the same information concerning the
                           underlying securities issuer as you would obtain and
                           evaluate if your investment were directly in the
                           underlying securities or in other securities issued
                           by the underlying securities issuer. There can be no
                           assurance that events affecting the underlying
                           securities or the underlying securities issuer have
                           not occurred or have not yet been publicly disclosed
                           which would affect the accuracy or completeness of
                           the publicly available documents described above.


SECTION 9.        FINANCIAL STATEMENTS AND EXHIBITS

         ITEM 9.01    FINANCIAL STATEMENTS AND EXHIBITS

                  (a) Financial statements of business acquired.

                      Not Applicable.

                  (b) Pro forma financial information.

                      Not Applicable.

                  (c) Shell company transactions.

                      Not Applicable

                  (c) Exhibits.

                      99.1   Trustee's report in respect of the April 3, 2006
                             distribution to holders of the PreferredPLUS Trust
                             Certificates Series CZN-1.

<PAGE>

                                   SIGNATURES

                  Pursuant to the requirements of the Securities Exchange Act of
                  1934, the registrant has duly caused this report to be signed
                  on its behalf by the undersigned, hereunto duly authorized.


                                        MERRILL LYNCH DEPOSITOR, INC.

         Date: April 12, 2006                  By:    /s/ Zvi Gillon
                                                      --------------------------
                                               Name:  Zvi Gillon
                                               Title: Vice President






                                  EXHIBIT INDEX


                   99.1    Trustee's report in respect of the April 3, 2006
                           distribution to holders of the PreferredPLUS Trust
                           Certificates Series CZN-1.
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{"company-data": {"conformed-name": "MERRILL LYNCH DEPOSITOR INC PREFERREDPLUS TRUST SER CZN 1", "cik": "0001157987", "assigned-sic": "6189", "irs-number": "000000000", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "001-16669", "film-number": "06756327"}, "business-address": {"street1": "WORLD FINANCIAL CENTER", "street2": "NORTH TOWER", "city": "NEW YORK", "state": "NY", "zip": "10281"}, "mail-address": {"street1": "WORLD FINANCIAL CENTER", "street2": "NORTH TOWER", "city": "NEW YORK", "state": "NY", "zip": "10281"}}
SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D. C. 20549
                           --------------------------

                                    FORM 8-K

                                 CURRENT REPORT

                       Pursuant to Section 13 or 15(d) of
                       The Securities Exchange Act of 1934
                            -------------------------

         Date of Report (Date of earliest event reported): April 3, 2006

                          MERRILL LYNCH DEPOSITOR, INC.
                 (ON BEHALF OF PREFERREDPLUS TRUST SERIES CZN-1)
             (Exact name of registrant as specified in its charter)

     DELAWARE                      001-16669                     13-3891329
 (State or other                 (Commission                 (I. R. S. Employer
 jurisdiction  of                 File Number)               Identification No.)
  incorporation)

        WORLD FINANCIAL CENTER,                                     10080
          NEW YORK, NEW YORK                                     (Zip Code)
         (Address of principal
          executive offices)
                           --------------------------

       Registrant's telephone number, including area code: (212) 449-1000

                      INFORMATION TO BE INCLUDED IN REPORT

Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions (see General Instruction A.2.):

[  ]  Written communications pursuant to Rule 425 under the Securities Act
      (17 CFR 230.425)

[  ]  Soliciting material pursuant to Rule 14a-12 under the Exchange Act
      (17 CFR 240.14a-12)

[  ]  Pre-commencement communications pursuant to Rule 14d-2(b) under the
      Exchange Act (17 CFR 240.14d-2(b))

[  ]  Pre-commencement communications pursuant to Rule 13e-4(c) under the
      Exchange Act (17 CFR 240.13e-4(c))
SECTION 1.        REGISTRANT'S BUSINESS AND OPERATIONS

                  Not applicable.

SECTION 2.        FINANCIAL INFORMATION

                  Not applicable.

SECTION 3.        SECURITIES AND TRADING MARKETS

                  Not applicable.

SECTION 4.        MATTERS RELATED TO ACCOUNTANTS AND FINANCIAL STATEMENTS

                  Not applicable.

SECTION 5.        CORPORATE GOVERNANCE AND MANAGEMENT

                  Not applicable.

SECTION 6.        ASSET-BACKED SECURITIES

                  Not applicable.

SECTION 7.        REGULATION FD

                  Not applicable.

SECTION 8.        OTHER EVENTS

         ITEM 8.01         OTHER EVENTS

                           99.1     Distribution to holders of the PreferredPLUS
                                    Trust Certificates Series CZN-1 on
                                    April 3, 2006.

                                    For information with respect to the
                           underlying securities held by PreferredPLUS Trust
                           Series CZN-1, please refer to Citizens Communications
                           Company's (Commission file number 001-11001) periodic
                           reports, including annual reports on Form 10-K,
                           quarterly reports on Form 10-Q and current reports on
                           Form 8-K, and other information on file with the
                           Securities and Exchange Commission (the "SEC"). You
                           can read and copy these reports and other information
                           at the public reference facilities maintained by the
                           SEC at Room 1580, 100 F Street, NE, Washington, D.C.
                           20549. You may obtain copies of this material for a
                           fee by writing to the SEC's Public Reference Section
                           of the SEC at 100 F Street, NE, Washington, D.C.
                           20549. You may obtain information about the operation
                           of the Public Reference Room by calling the SEC at
                           1-800-SEC-0330. You can also access some of this
                           information electronically by means of the SEC's
                           website on the Internet at http://www.sec.gov, which
                           contains reports, proxy and information statements
                           and other information that the underlying securities
                           issuer has filed electronically with the SEC.
Although we have no reason to
                           believe the information concerning the underlying
                           securities or the underlying securities issuer
                           contained in the underlying securities issuer's
                           Exchange Act reports is not reliable, neither the
                           depositor nor the trustee participated in the
                           preparation of such documents or made any due
                           diligence inquiry with respect to the information
                           provided therein. No investigation with respect to
                           the underlying securities issuer (including, without
                           limitation, no investigation as to its financial
                           condition or creditworthiness) or of the underlying
                           securities has been made. You should obtain and
                           evaluate the same information concerning the
                           underlying securities issuer as you would obtain and
                           evaluate if your investment were directly in the
                           underlying securities or in other securities issued
                           by the underlying securities issuer. There can be no
                           assurance that events affecting the underlying
                           securities or the underlying securities issuer have
                           not occurred or have not yet been publicly disclosed
                           which would affect the accuracy or completeness of
                           the publicly available documents described above.

SECTION 9.        FINANCIAL STATEMENTS AND EXHIBITS

         ITEM 9.01    FINANCIAL STATEMENTS AND EXHIBITS

                  (a) Financial statements of business acquired.

                      Not Applicable.

                  (b) Pro forma financial information.

                      Not Applicable.

                  (c) Shell company transactions.

                      Not Applicable

                  (c) Exhibits.

                      99.1   Trustee's report in respect of the April 3, 2006
                             distribution to holders of the PreferredPLUS Trust
                             Certificates Series CZN-1.
SIGNATURES

                  Pursuant to the requirements of the Securities Exchange Act of
                  1934, the registrant has duly caused this report to be signed
                  on its behalf by the undersigned, hereunto duly authorized.

                                        MERRILL LYNCH DEPOSITOR, INC.

         Date: April 12, 2006                  By:    /s/ Zvi Gillon
                                                      --------------------------
                                               Name:  Zvi Gillon
                                               Title: Vice President

                                  EXHIBIT INDEX

                   99.1    Trustee's report in respect of the April 3, 2006
                           distribution to holders of the PreferredPLUS Trust
                           Certificates Series CZN-1.