4-Substituted 2-(N,N-di(het)arylamino)thiazole derivatives of the following general structures VIe, VIm, VIp and VIt: wherein: - R 1, R 2 and R 3 are, mutually independently, in each case a monofunctional (het)aryl system, i.e. a conjugated carbocyclic or heterocyclic ring system which may also consist of linearly or angularly anellated or linked identical or different ring types, wherein the peripheral hydrogen atoms may optionally be substituted by alkyl, alkoxy, dialkylamino or diphenylamio groups (alkyl = C 1 to C 6); - R 7 is an arylene system, - Z- is any desired anion, in particular an organic sulfonate, - Y is -CH or -N; and 4-substituted 2-(N,N-di(het)arylamino)thiazole derivatives of the following general structures VIb, VIf, VIh and VIu: wherein: - R 1 is a corresponding difunctional (het)arylene system, i.e. a conjugated carbocyclic or heterocyclic ring system which may also consist of linearly or angularly anellated or linked identical or different ring types, wherein the peripheral hydrogen atoms may optionally be substituted by alkyl, alkoxy, dialkylamino or diphenylamino groups (alkyl = C 1 to C 6); - R 2 and R 3 are, mutually independently, in each case a monofunctional (het)aryl system, i.e. a conjugated carbocyclic or heterocyclic ring system which may also consist of linearly or angularly anellated or linked identical or different ring types, wherein the peripheral hydrogen atoms may optionally be substituted by alkyl, alkoxy, dialkylamino or diphenylamio groups (alkyl = C 1 to C 6); - R 4 is wherein, within the definition of residue R 4, the residues R 1 R 2 and R 3 correspond to residues R 1, R 2 and R 3 as defined for the structures VIe, VIm, VIp and VIt; - R 7 denotes a chemical bond or a difunctional (het)arylene system; - n means an integer from 2 to 100, - Z- is an anion, in particular an organic sulfonate, - Y is -CH or -N. - R 1, R 2 and R 3 are, mutually independently, in each case a monofunctional (het)aryl system, i.e. a conjugated carbocyclic or heterocyclic ring system which may also consist of linearly or angularly anellated or linked identical or different ring types, wherein the peripheral hydrogen atoms may optionally be substituted by alkyl, alkoxy, dialkylamino or diphenylamio groups (alkyl = C 1 to C 6); - R 7 is an arylene system, - Z- is any desired anion, in particular an organic sulfonate, - Y is -CH or -N; - R 1 is a corresponding difunctional (het)arylene system, i.e. a conjugated carbocyclic or heterocyclic ring system which may also consist of linearly or angularly anellated or linked identical or different ring types, wherein the peripheral hydrogen atoms may optionally be substituted by alkyl, alkoxy, dialkylamino or diphenylamino groups (alkyl = C 1 to C 6); - R 2 and R 3 are, mutually independently, in each case a monofunctional (het)aryl system, i.e. a conjugated carbocyclic or heterocyclic ring system which may also consist of linearly or angularly anellated or linked identical or different ring types, wherein the peripheral hydrogen atoms may optionally be substituted by alkyl, alkoxy, dialkylamino or diphenylamio groups (alkyl = C 1 to C 6); - R 4 is wherein, within the definition of residue R 4, the residues R 1 R 2 and R 3 correspond to residues R 1, R 2 and R 3 as defined for the structures VIe, VIm, VIp and VIt; - R 7 denotes a chemical bond or a difunctional (het)arylene system; - n means an integer from 2 to 100, - Z- is an anion, in particular an organic sulfonate, - Y is -CH or -N.