Coloring agents and methods of use thereof

A functionalized dye comprising at least one chromophore and a color fastness moiety, wherein the chromophore is bound to the color fastness moiety by a linker, wherein said dye is a compound of formula Ia:

• C-L-F (Ia), wherein
• C is a chromophore represented by the following structural formula:
• wherein
• R26a is attached to linker L;
• L is a linker of formula (III):
• wherein
• L covalently links the chromophore C via the left hand side of formula III to the color fastness moiety F via the right hand side of formula III;
• a, b, c, d, e, and f are each independently an integer from 0-2, provided that at least one of a, b, c, d, e and f is not 0;
• R40, R41, R42, R43, R44, R45, R46, R47, R48, R49, R50 and R51 are each independently hydrogen or absent;
• E is NR52 or NR53C═O;
• R52 and R53 are each independently hydrogen or alkyl;
• F is a color fastness moiety of formula (Va):
• wherein
• m, n, o, p, q and r are each independently an integer from 0-2, provided that at least one of m, n, o, p, q and r is not 0;
• R78, R79, R80, R81, R82, R83, R84, R85, R87, R88 and R89 are each independently hydrogen or absent;
• R86 is hydrogen or hydroxyl;
• K is NR90 or C(═O)NR92;
• W is NR95R96, CR97R98R99 or OR100;
• R90 and R92 are each independently hydrogen or alkyl;
• R95 is alkyl and R96 is hydrogen or alkyl, or R95 and R96, together with the nitrogen to which they are attached are linked to form an 4-8-membered heterocyclic ring comprising 1-3 heteroatoms;
• R97, R98 and R99 are independently selected from hydrogen, alkyl, alkoxy, hydroxyl, or heteroaryl;
• and
• R100 is hydrogen or alkyl;
• or a cosmetically acceptable salt thereof.