Sec Form 4 Filing - ARDSLEY ADVISORY PARTNERS @ LIGHTING SCIENCE GROUP CORP - 2007-04-13

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person ARDSLEY ADVISORY PARTNERS 2. Issuer Name and Ticker or Trading Symbol LIGHTING SCIENCE GROUP CORP [ LSGP.OB] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 262 HARBOR DRIVE, 4TH FLOOR 3. Date of Earliest Transaction (MM/DD/YY) 04/13/2007 (Street) STAMFORD, CT06902 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock, par value $0.001 04/13/2007 P 50,000 A ( 3 ) $ 0.271 11,716,665 I See Footnotes ( 1 ) ( 2 ) Common Stock, par value $0.001 04/17/2007 P 25,000 A ( 3 ) $ 0.2924 11,741,665 I See Footnotes ( 1 ) ( 2 ) Common Stock, par value $0.001 04/20/2007 P 50,000 A ( 3 ) $ 0.2992 11,791,665 I See Footnotes ( 1 ) ( 2 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other ARDSLEY ADVISORY PARTNERS 262 HARBOR DRIVE, 4TH FLOOR STAMFORD, CT06902 X Signatures ARDSLEY PARTNERS RENEWABLE ENERGY FUND, L.P., BY: ARDSLEY PARTNERS I, GENERAL PARTNER, BY: /s/ Steve Napoli,* General Partner 05/02/2007 Signature of Reporting Person Date ARDSLEY RENEWABLE ENERGY OFFSHORE FUND, LTD., BY: /s/ Steve Napoli, Director 05/02/2007 Signature of Reporting Person Date ARDSLEY ADVISORY PARTNERS, BY: ARDSLEY PARTNERS I, GENERAL PARTNER, BY: /s/ Steve Napoli,* General Partner 05/02/2007 Signature of Reporting Person Date ARDSLEY PARTNERS I, BY PHILIP J. HEMPLEMEN, GENERAL PARTNER, BY: /s/ Steve Napoli,* General Partner 05/02/2007 Signature of Reporting Person Date PHILIP J. HEMPLEMAN, INDIVIDUALLY, BY: Steve Napoli,* As attorney in fact for Philip J. Hempleman 05/02/2007 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Ardsley Renewable Energy Offshore Fund, Ltd., a British Virgin Islands corporation ("Ardsley Offshore") directly holds 246,662 shares of Common Stock and immediately exercisable warrants for an additional 304,155 shares of Common Stock. Ardsley Partners Renewable Energy Fund, L.P., a Delaware limited partnership ("Ardsley Domestic") located at c/o Ardsley Partners I, 262 Harbor Drive, Stamford, Connecticut 06902, directly holds 3,211,671 shares of Common Stock and immediately exercisable warrants for an additional 8,029,177 shares of Common Stock. ( 2 )Ardsley Advisory Partners, a New York general partnership ("Ardsley") serves as investment manager to, and has investment discretion over the securities held by Ardsley Offshore, and serves as investment adviser to Ardsley Domestic. Phillip J. Hempleman and Ardsley Partners I, a New York general partnership ("Ardsley Partners") serve as the general partners of Ardsley Domestic. Ardsley Partners also serves as the general partner of Ardsley. Philip J. Hempleman, Ardsley and Ardsley Partners each disclaim any beneficial ownership of any of the Issuer's securities to which this Form 4 relates for the purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except as to such securities in which each such person may be deemed to have an indirect pecuniary interest pursuant to Rule 16a-1(a)(2). ( 3 )Common Stock purchased by Ardsley Offshore.

Remarks: * Evidence of Power of Attorney was submitted with the Schedule 13G filed by Ardsley Advisory Partners on February 14, 2006 and is incorporated by reference herein.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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