A compound of formula: wherein - W is a nitrogen atom; - V is, on each occurrence, identically or differently selected from C(R 1) 2, C=O or O, R 1 being selected from C1-C12 alkyl; - L is selected from moiety of formula ------ n -(Ac) m -Ar as defined below or from moiety of formula p being 0, 1 or 2 and moiety of formula ------ n - m -Ar being as defined below; - Z is a heteroaromatic ring system, on each occurrence, identically or differently selected from C4-C20 heteroaryl and C4-C20 heteroaryloxy group, wherein the heteroatoms are selected from O, S, Se, Si and wherein said heteroaryland heteroaryloxy group are substituted by C1-C20 alkyl, C1-C20 heteroalkyl, C2-C20 alkenyl or C2-C20 alkynyl, wherein said alkyl, alkenyl, and alkynyl, if they comprise 3 or more carbons, may be linear, branched or cyclic, and n is 0, 1, 2, or 3; - Ac is an acceptor group, on each occurrence, identically or differently selected from a moiety according to any one of the formulae to, - wherein - R 2 to R 37 are substituents independently selected from H, ether group, C1-C 16 alkyl, C1-C16 alkoxy group, C1-C16 thioalkyl, C1-C16 alkoxyalkyl, C4-C16 aryl, C1-C16 arylalkyl or C4-C16 heteroaryl, C4-C16 heteroarylalkyl, the heteroatoms being selected from O, S, or N, - Q is selected from S, O, Se, Si or N and when Q is N, said nitrogen atom is substituted by substituent as defined for R 2 to R 37, - Y is, on each occurrence, identically or differently selected from N or C, being unsubstituted or substituted by halogen selected from F, Cl, I, and Br, and - m is 0 or 1; - -Ar is a successive bound heteroaromatic rings system comprising from 2 to 10 heteroaromatic rings, said heteroaromatic rings being, on each occurrence, identically selected from C4-C20 heteroaryl and C4-C20 heteroaryloxy group, wherein the heteroatoms are selected from O, S, Se, Si and wherein said heteroaryl and heteroaryloxy groups are unsubstituted or substituted by -COOH, C4-C16 cyanoalkenyl carboxylic acid, C1-C20 alkyl, C1-C20 heteroalkyl, C2-C20 alkenyl or C2-C20 alkynyl, wherein said alkyl, alkenyl, and alkynyl, if they comprise 3 or more carbons, may be linear, branched or cyclic. - W is a nitrogen atom; - V is, on each occurrence, identically or differently selected from C(R 1) 2, C=O or O, R 1 being selected from C1-C12 alkyl; - L is selected from moiety of formula ------ n -(Ac) m -Ar as defined below or from moiety of formula p being 0, 1 or 2 and moiety of formula ------ n - m -Ar being as defined below; - Z is a heteroaromatic ring system, on each occurrence, identically or differently selected from C4-C20 heteroaryl and C4-C20 heteroaryloxy group, wherein the heteroatoms are selected from O, S, Se, Si and wherein said heteroaryland heteroaryloxy group are substituted by C1-C20 alkyl, C1-C20 heteroalkyl, C2-C20 alkenyl or C2-C20 alkynyl, wherein said alkyl, alkenyl, and alkynyl, if they comprise 3 or more carbons, may be linear, branched or cyclic, and n is 0, 1, 2, or 3; - Ac is an acceptor group, on each occurrence, identically or differently selected from a moiety according to any one of the formulae to, - wherein - R 2 to R 37 are substituents independently selected from H, ether group, C1-C 16 alkyl, C1-C16 alkoxy group, C1-C16 thioalkyl, C1-C16 alkoxyalkyl, C4-C16 aryl, C1-C16 arylalkyl or C4-C16 heteroaryl, C4-C16 heteroarylalkyl, the heteroatoms being selected from O, S, or N, - Q is selected from S, O, Se, Si or N and when Q is N, said nitrogen atom is substituted by substituent as defined for R 2 to R 37, - Y is, on each occurrence, identically or differently selected from N or C, being unsubstituted or substituted by halogen selected from F, Cl, I, and Br, and - m is 0 or 1; - R 2 to R 37 are substituents independently selected from H, ether group, C1-C 16 alkyl, C1-C16 alkoxy group, C1-C16 thioalkyl, C1-C16 alkoxyalkyl, C4-C16 aryl, C1-C16 arylalkyl or C4-C16 heteroaryl, C4-C16 heteroarylalkyl, the heteroatoms being selected from O, S, or N, - Q is selected from S, O, Se, Si or N and when Q is N, said nitrogen atom is substituted by substituent as defined for R 2 to R 37, - Y is, on each occurrence, identically or differently selected from N or C, being unsubstituted or substituted by halogen selected from F, Cl, I, and Br, and - m is 0 or 1; - -Ar is a successive bound heteroaromatic rings system comprising from 2 to 10 heteroaromatic rings, said heteroaromatic rings being, on each occurrence, identically selected from C4-C20 heteroaryl and C4-C20 heteroaryloxy group, wherein the heteroatoms are selected from O, S, Se, Si and wherein said heteroaryl and heteroaryloxy groups are unsubstituted or substituted by -COOH, C4-C16 cyanoalkenyl carboxylic acid, C1-C20 alkyl, C1-C20 heteroalkyl, C2-C20 alkenyl or C2-C20 alkynyl, wherein said alkyl, alkenyl, and alkynyl, if they comprise 3 or more carbons, may be linear, branched or cyclic.