<SEC-DOCUMENT>0001537435-25-000060.txt : 20250624
<SEC-HEADER>0001537435-25-000060.hdr.sgml : 20250624
<ACCEPTANCE-DATETIME>20250624121424
ACCESSION NUMBER:		0001537435-25-000060
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20240423
FILED AS OF DATE:		20250624
DATE AS OF CHANGE:		20250624

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Deschenes Roger P.
		CENTRAL INDEX KEY:			0001496259
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36103
		FILM NUMBER:		251067653

	MAIL ADDRESS:	
		STREET 1:		C/O IMPLANT SCIENCES CORPORATION
		STREET 2:		500 RESEARCH DRIVE
		CITY:			WILMINGTON
		STATE:			MA
		ZIP:			01887

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			TECOGEN INC.
		CENTRAL INDEX KEY:			0001537435
		STANDARD INDUSTRIAL CLASSIFICATION:	AIR COND & WARM AIR HEATING EQUIP & COMM & INDL REFRIG EQUIP [3585]
		ORGANIZATION NAME:           	06 Technology
		EIN:				043536131
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		76 TREBLE COVE ROAD
		STREET 2:		BLDG. 1
		CITY:			NORTH BILLERICA
		STATE:			MA
		ZIP:			01862
		BUSINESS PHONE:		781-466-6400

	MAIL ADDRESS:	
		STREET 1:		76 TREBLE COVE ROAD
		STREET 2:		BLDG. 1
		CITY:			NORTH BILLERICA
		STATE:			MA
		ZIP:			01862

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	TECOGEN INC
		DATE OF NAME CHANGE:	20111215
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>wk-form3_1750781657.xml
<DESCRIPTION>FORM 3
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2024-04-23</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001537435</issuerCik>
        <issuerName>TECOGEN INC.</issuerName>
        <issuerTradingSymbol>TGEN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001496259</rptOwnerCik>
            <rptOwnerName>Deschenes Roger P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>76 TREBLE COVE ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NORTH BILLERICA</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>01862</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CAO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>24998</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Options (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.78</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2030-09-21</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>50000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Options (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.10</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2023-01-21</value>
            </exerciseDate>
            <expirationDate>
                <value>2032-01-21</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>52500</value>
                    <footnoteId id="F2"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.88</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2024-09-20</value>
            </exerciseDate>
            <expirationDate>
                <value>2033-09-20</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>37500</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Vests 50% upon achievement of Adjusted EBITDA goal of 2% of revenue in two consecutive quarters, and 50% upon achievement of Adjusted EBITDA goal of 3% of revenue in four consecutive quarters</footnote>
        <footnote id="F2">Vests 50% per year</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Roger P. Deschenes</signatureName>
        <signatureDate>2025-06-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
