A
subject matter of the invention is
cyanine derivatives of formula:in which the dotted lines represent the atoms necessary for the formation of one or two fused aromatic rings, each ring comprising 5 or 6 carbon atoms;R1, R2, R3 and R4 represent, independently of one another: H; substituted or unsubstituted C1-C15
alkyl; C1-C6 alkoxy; (C2-C12)dialkylamino; C1-C6 alkoxycarbonyl; di(C2-C12)alkylamido; a substituted or unsubstituted
aryl, arylalkyl or aryloxy group; a
halogen atom; a nitro; an L1-W, L2-M, L2-A or L2-G group;R5 and R6 represent, independently of one another: substituted or unsubstituted C1-C15
alkyl; a substituted or unsubstituted
aryl or arylalkyl group; an L1-W, L2-M, L2-A or L2-G group;X is chosen from: O, S or CR7R8; Y is chosen from: O, S or CR9R10;R7, R8, R9 and R10 independently represent: substituted or unsubstituted C1-C15
alkyl; substituted or unsubstituted
aryl, arylalkyl or aryloxy; an L1-W, L2-M, L2-A or L2-G group;R7 and R8 and / or R9 and R10 can also together form a ring comprising 5 or 6 atoms or a heterocycle comprising 4 to 5 carbon atoms and an
oxygen atom;B represents a polymethine bridge comprising 1 to 5 methine groups, said groups being in particular individually unsubstituted or substituted by a substituted or unsubstituted C1-C15 alkyl; a substituted or unsubstituted aryl, arylalkyl or aryloxy group; a nitro group; an L1-W, L2-M, L2-A or L2-G group;L1 and L2 are connecting arms; G is a reactive group; A is a
coupling agent; M is a conjugated molecule, W is a
phosphate or
phosphonate ester (preferably diester), with the proviso that the
cyanine derivative comprises at least one L1-W group and at least one L2-A, L2-G or L2-M group.