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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 18pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"></P>

<!-- Field: Rule-Page --><DIV ALIGN="CENTER" STYLE="margin-top: 3pt; margin-bottom: 3pt"><DIV STYLE="font-size: 1pt; border-top: Black 4pt solid; width: 100%">&nbsp;</DIV></DIV><!-- Field: /Rule-Page -->

<P STYLE="font: 18pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>SECURITIES AND EXCHANGE COMMISSION </B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>WASHINGTON, D.C. 20549 </B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 18pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>FORM 8-K </B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>CURRENT REPORT </B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Pursuant to Section 13 or 15(d) of the
</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Securities Exchange Act of 1934 </B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Date of report (Date of earliest event
reported): May 15, 2012</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 18pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>CLEARSIGN COMBUSTION CORPORATION</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>(Exact name of registrant as specified
in Charter) </B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B>&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 32%; font-weight: bold; text-align: center">Washington</TD>
    <TD STYLE="width: 3%">&nbsp;</TD>
    <TD STYLE="width: 31%; font-weight: bold; text-align: center">001-35521</TD>
    <TD STYLE="width: 3%">&nbsp;</TD>
    <TD STYLE="width: 31%; font-weight: bold; text-align: center">26-2056298</TD></TR>
<TR STYLE="vertical-align: top">
    <TD>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>(State or other jurisdiction of</B></P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>incorporation or organization)</B></P></TD>
    <TD>&nbsp;</TD>
    <TD STYLE="font-weight: bold; text-align: center">(Commission File No.)</TD>
    <TD>&nbsp;</TD>
    <TD STYLE="font-weight: bold; text-align: center">(IRS Employee Identification No.)</TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>12870 Interurban Avenue South</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Seattle, Washington 98168</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>(Address of Principal Executive Offices)
</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>206-673-4848</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>(Issuer Telephone number) </B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">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 below).</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><FONT STYLE="font-family: Wingdings">&uml;</FONT> Written communications
pursuant to Rule 425 under the Securities Act (17 CFR 230.425)</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><FONT STYLE="font-family: Wingdings">&uml;</FONT> Soliciting
material pursuant to Rule 14a-12 under the Exchange Act (17 CFR240.14a-12)</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><FONT STYLE="font-family: Wingdings">&uml;</FONT> Pre-commencement
communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)).</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><FONT STYLE="font-family: Wingdings">&uml;</FONT> Pre-commencement
communications pursuant to Rule 13e-(c) under the Exchange Act (17 CFR 240.13(e)-4(c))</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>Item 8.01&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Other Events</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 63pt; text-indent: -63pt">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">On May 15, 2012, ClearSign Combustion Corporation
(&ldquo;we&rdquo; or &ldquo;our&rdquo;) issued a press release announcing that our underwriter, MDB Capital Group LLC, exercised
in full its over-allotment option to purchase an additional 450,000 shares of our common stock at a price of $4.00 per share, for
gross proceeds of $1.8 million. The net proceeds of the over-allotment after deducting underwriting discounts and commissions and
estimated offering expenses are expected to be approximately $1,642,500. With the exercise of the over-allotment option, the gross
proceeds of our initial public offering total $13.8 million. The press release is included as Exhibit 99.1 to this Current Report
on Form 8-K, and is incorporated by reference herein. The description of the press release is qualified in its entirety by reference
to such Exhibit.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>Item 9.01&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Financial Statements and Exhibits</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">Exhibit 99.1&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Press release dated May
15, 2012</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0">SIGNATURE</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 1in">Pursuant to the requirements of the Securities
Exchange Act of 1934, the registrant has duly caused this Current Report to be signed on its behalf by the undersigned hereunto
duly authorized.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Dated: May 15, 2012</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

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<TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD COLSPAN="2">CLEARSIGN COMBUSTION CORPORATION</TD></TR>
<TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD COLSPAN="2">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 50%">&nbsp;</TD>
    <TD STYLE="width: 5%">By:</TD>
    <TD STYLE="width: 45%; border-bottom: Black 1pt solid">/s/ James N. Harmon</TD></TR>
<TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>James N. Harmon</TD></TR>
<TR STYLE="vertical-align: top">
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>Chief Financial Officer</TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 2.5in; text-indent: 0.5in">&nbsp;</P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>EXHIBIT INDEX</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 15%; font-weight: bold">Exhibit No.</TD>
    <TD STYLE="width: 85%; font-weight: bold">Description</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-weight: bold">&nbsp;</TD>
    <TD STYLE="font-weight: bold">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD>99.1</TD>
    <TD>Press release dated May 15, 2012</TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: right">&nbsp;</P>

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[{"type": "8-K", "sequence": "1", "filename": "v313475_8k.htm", "description": "FORM 8-K", "secsgml_size_bytes": 12546}]
{"company-data": {"conformed-name": "CLEARSIGN COMBUSTION CORP", "cik": "0001434524", "assigned-sic": "3823", "irs-number": "000000000", "state-of-incorporation": "WA"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "001-35521", "film-number": "12844466"}, "business-address": {"street1": "12870 INTERURBAN AVENUE SOUTH", "city": "SEATTLE", "state": "WA", "zip": "98168", "phone": "(206) 673-4848"}, "mail-address": {"street1": "12870 INTERURBAN AVENUE SOUTH", "city": "SEATTLE", "state": "WA", "zip": "98168"}}
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): May 15, 2012
CLEARSIGN COMBUSTION CORPORATION
(Exact name of registrant as specified
in Charter)
Washington
001-35521
26-2056298
(State or other jurisdiction of
incorporation or organization)
(Commission File No.)
(IRS Employee Identification No.)
12870 Interurban Avenue South
Seattle, Washington 98168
(Address of Principal Executive Offices)
206-673-4848
(Issuer Telephone number)
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 below).
¨
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 CFR240.14a-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-(c) under the Exchange Act (17 CFR 240.13(e)-4(c))
Item 8.01          Other Events
On May 15, 2012, ClearSign Combustion Corporation
("we" or "our") issued a press release announcing that our underwriter, MDB Capital Group LLC, exercised
in full its over-allotment option to purchase an additional 450,000 shares of our common stock at a price of $4.00 per share, for
gross proceeds of $1.8 million. The net proceeds of the over-allotment after deducting underwriting discounts and commissions and
estimated offering expenses are expected to be approximately $1,642,500. With the exercise of the over-allotment option, the gross
proceeds of our initial public offering total $13.8 million. The press release is included as Exhibit 99.1 to this Current Report
on Form 8-K, and is incorporated by reference herein. The description of the press release is qualified in its entirety by reference
to such Exhibit.
Item 9.01          Financial Statements and Exhibits
Exhibit 99.1          Press release dated May
15, 2012
SIGNATURE
Pursuant to the requirements of the Securities
Exchange Act of 1934, the registrant has duly caused this Current Report to be signed on its behalf by the undersigned hereunto
duly authorized.
Dated: May 15, 2012
CLEARSIGN COMBUSTION CORPORATION
By:
/s/ James N. Harmon
James N. Harmon
Chief Financial Officer
EXHIBIT INDEX
Exhibit No.
Description
99.1
Press release dated May 15, 2012