Chemical compound of general formula I: a) where n, m are each independently of one another 0, 1 or 2; b) where X1, X2 are each independently of one another selected from halogen, CN, alkyl, fluorinated or partially fluorinated alkyl, alkenyl, alkynyl, alkoxy, aryl or heteroaryl; c) where EWG is CF 3 ; d) where z1 and z2 are selected from the groups (II) to (IV) : wherein "*" in each case describes a potential bonding site of the substituents z1, z2 to the dipyrrine backbone and to the aryl substituents Ar1, Ar2, e) where R1 to R4 are each independently of one another selected from H or an alkyl; f) where R5 and R6 are each independently of one another selected from H, halogen, CN, a substituted or unsubstituted, branched or unbranched, linear or cyclic alkyl chain; g) wherein Ar1 in the case of n = 0 and/or Ar2 in the case of m = 0 correspond to formula (V) and "*" describes the bonding site of the substituents Ar1, Ar2 to the dipyrrine backbone, wherein X is selected from N or C-R8, wherein Y is selected from N or C-R9, wherein R7 to R9 are independently of one another selected from a group consisting of H, halogen, branched or linear, cyclic or open-chain alkyl or aryl, wherein H-atoms and/or C-atoms of the alkyl or aryl may be substituted, or from a group consisting of alkenyl, O-alkyl, S-alkyl, O-alkenyl, S-alkenyl, alkynyl, aryl or heteroaryl, wherein in all these groups H-atoms may be substituted, or from CN or NR'R", where R' and R" are each independently of one another selected from: H, branched or linear, cyclic or open-chain alkyl, wherein H- and/or C-atoms of the alkyl may be substituted or wherein R7 and R9 may together form a homocyclic or heterocyclic, saturated or unsaturated, substituted or unsubstituted ring, and wherein Ar1 in the case of n > 0 and/or Ar2 in the case of m > 0 is a substituted or unsubstituted heterocyclic 5-membered ring, preferably having heteroatom selected from S or O. a) where n, m are each independently of one another 0, 1 or 2; b) where X1, X2 are each independently of one another selected from halogen, CN, alkyl, fluorinated or partially fluorinated alkyl, alkenyl, alkynyl, alkoxy, aryl or heteroaryl; c) where EWG is CF 3 ; d) where z1 and z2 are selected from the groups (II) to (IV) : wherein "*" in each case describes a potential bonding site of the substituents z1, z2 to the dipyrrine backbone and to the aryl substituents Ar1, Ar2, e) where R1 to R4 are each independently of one another selected from H or an alkyl; f) where R5 and R6 are each independently of one another selected from H, halogen, CN, a substituted or unsubstituted, branched or unbranched, linear or cyclic alkyl chain; g) wherein Ar1 in the case of n = 0 and/or Ar2 in the case of m = 0 correspond to formula (V) and "*" describes the bonding site of the substituents Ar1, Ar2 to the dipyrrine backbone, wherein X is selected from N or C-R8, wherein Y is selected from N or C-R9, wherein R7 to R9 are independently of one another selected from a group consisting of H, halogen, branched or linear, cyclic or open-chain alkyl or aryl, wherein H-atoms and/or C-atoms of the alkyl or aryl may be substituted, or from a group consisting of alkenyl, O-alkyl, S-alkyl, O-alkenyl, S-alkenyl, alkynyl, aryl or heteroaryl, wherein in all these groups H-atoms may be substituted, or from CN or NR'R", where R' and R" are each independently of one another selected from: H, branched or linear, cyclic or open-chain alkyl, wherein H- and/or C-atoms of the alkyl may be substituted or wherein R7 and R9 may together form a homocyclic or heterocyclic, saturated or unsaturated, substituted or unsubstituted ring, and <EOS>