A compound of formula wherein - M is selected from Co, Cu, Fe, Mg, Mn, Ni, Si or Zn or M is two H (hydrogen) substituting two pyrrole moieties constituting the porphyrin core; - A is an acceptor group selected from a moiety according to any one of the formulae to and to wherein R 1 -R 68 and R 137 -R 141 are substituents independently selected from H, C1-C16 alkyl, C1-C16 alkoxy, C1-C16 thioalkyl, C1-C16 alkoxyalkyl, C4-C16 aryl, C1-C16 arylalkyl or C4-C16 heteroaryl, C4-C16 heteroarylalkyl wherein heteroatoms are selected from O, S, or N; - Anc is an anchoring group selected from C4-C16 aryl or C4-C16 heteroaryl being further substituted, wherein heteroatoms are selected from O, S, or N and wherein further substituents are selected from COOH, =O (keto), C4-C16 cyanoalkenyl carboxylic acid; - L 1 and L 2 are substituents independently selected from C4-C16 aryl or C4-C16 heteroaryl being further substituted or unsubstituted, wherein heteroatoms are selected from O, S, or N and wherein the further substituents are selected from H, C1-C16 alkyl, C1-C16 alkoxy, C1-C16 thioalkyl, C1-C16 alkoxyalkyl, C4-C16 aryl, C1-C16 arylalkyl or C4-C16 heteroaryl, C4-C16 heteroarylalkyl wherein heteroatoms are selected from O, S, or N; - Ar 1 and Ar 2 are donor substituents being selected from C4-C16 aryl, C8-C32-diaryl, C4-C16 heteroaryl being further substituted or unsubstituted, wherein heteroatoms are selected from O, S, or N and wherein the further substituents are selected from H, C1-C16 alkyl, C1-C16 alkoxy, C1-C16 thioalkyl, C1-C16 alkoxyalkyl, C4-C16 aryl, C1-C16 arylalkyl or C4-C16 heteroaryl, C4-C16 heteroarylalkyl wherein heteroatoms are selected from O, S, or N. - M is selected from Co, Cu, Fe, Mg, Mn, Ni, Si or Zn or M is two H (hydrogen) substituting two pyrrole moieties constituting the porphyrin core; - A is an acceptor group selected from a moiety according to any one of the formulae to and to wherein R 1 -R 68 and R 137 -R 141 are substituents independently selected from H, C1-C16 alkyl, C1-C16 alkoxy, C1-C16 thioalkyl, C1-C16 alkoxyalkyl, C4-C16 aryl, C1-C16 arylalkyl or C4-C16 heteroaryl, C4-C16 heteroarylalkyl wherein heteroatoms are selected from O, S, or N; - Anc is an anchoring group selected from C4-C16 aryl or C4-C16 heteroaryl being further substituted, wherein heteroatoms are selected from O, S, or N and wherein further substituents are selected from COOH, =O (keto), C4-C16 cyanoalkenyl carboxylic acid; - L 1 and L 2 are substituents independently selected from C4-C16 aryl or C4-C16 heteroaryl being further substituted or unsubstituted, wherein heteroatoms are selected from O, S, or N and wherein the further substituents are selected from H, C1-C16 alkyl, C1-C16 alkoxy, C1-C16 thioalkyl, C1-C16 alkoxyalkyl, C4-C16 aryl, C1-C16 arylalkyl or C4-C16 heteroaryl, C4-C16 heteroarylalkyl wherein heteroatoms are selected from O, S, or N; - Ar 1 and Ar 2 are donor substituents being selected from C4-C16 aryl, C8-C32-diaryl, C4-C16 heteroaryl being further substituted or unsubstituted, wherein heteroatoms are selected from O, S, or N and wherein the further substituents are selected from H, C1-C16 alkyl, C1-C16 alkoxy, C1-C16 thioalkyl, C1-C16 alkoxyalkyl, C4-C16 aryl, C1-C16 arylalkyl or C4-C16 heteroaryl, C4-C16 heteroarylalkyl wherein heteroatoms are selected from O, S, or N.