Polymeric dyes having a backbone comprising organophosphate units

A compound having the following structure (In):

• or a stereoisomer, salt or tautomer thereof, wherein:
• M2 is, at each occurrence, independently a fluorescent or colored moiety comprising two or more double bonds and at least one degree of conjugation;
• L6 and L7 are, at each occurrence, independently optional alkylene, alkenylene, alkynylene, heteroalkylene, heteroalkenylene or heteroalkynylene linkers;
• R1 and R2 are each independently H, OH, SH, alkyl, alkoxy, alkylether, heteroalkyl, —OP(═Ra)(Rb)Rc, Q, or a protected form thereof, or L′;
• R3 is, at each occurrence, independently H, alkyl or alkoxy;
• Ra is O or S;
• Rb is OH, SH, O−, S−, ORd or SRd;
• Rc is OH, SH, O−, S−, ORd, OL′, SRd, alkyl, alkoxy, heteroalkyl, heteroalkoxy, alkylether, alkoxyalkylether, phosphate, thiophosphate, phosphoalkyl, thiophosphoalkyl, phosphoalkylether or thiophosphoalkylether;
• Rd is a counter ion;
• Q is, at each occurrence, independently a moiety comprising a reactive group, or protected form thereof, capable of forming a covalent bond with an analyte molecule, a targeting moiety, a solid support or a complementary reactive group Q′;
• L′ is, at each occurrence, independently a linker comprising a covalent bond to Q, a linker comprising a covalent bond to a targeting moiety, a linker comprising a covalent bond to an analyte molecule, a linker comprising a covalent bond to a solid support, a linker comprising a covalent bond to a solid support residue, a linker comprising a covalent bond to a nucleoside or a linker comprising a covalent bond to a further compound of structure (In);
• n is an integer of one or greater;
• s is, at each occurrence, independently an integer of 1 or greater;
• z is, at each occurrence, independently an integer from 20 to 30;
• p is, at each occurrence, independently an integer of one or greater;
• R4 is, at each occurrence, independently OH, SH, O−, S−, ORd or SRd;
• R5 is, at each occurrence, independently oxo, thioxo or absent;
• and
• at least one occurrence of M2 has one of the following structures: