Water-soluble heterocyclyl polymethine chromophores

A compound of formula I:

• wherein:
• R1 and R2 are each independently selected from H, alkyl, or halo;
• or R1 and R2 together complete a cycloalkenyl ring, a heterocyclyl ring, or a polycyclyl ring system;
• R9 is H, alkyl, alkoxy, haloalkyl or halo;
• R10 is H, alkyl, alkoxy, haloalkyl or halo;
• R11 and R12 are each independently H, C3-C10 alkyl or cycloalkyl;
• and
• R13 is H, alkynyl-alkyl, alkynyl, heteroaralkyl, heteroaryl, a group comprising an azide, heteroaralkyl, or a moiety that comprises a reactive group capable of undergoing bioconjugation, or a group comprising an acid, aldehyde, alkene, hydroxyl, amide, urea or sulfonamide;
• and
• A and B are each independently selected from a bicyclic, tricyclic, or tetracyclic heteroaryl;
• wherein A and B are each independently substituted with one or more R14a and/or R14b,
• wherein each R14a and/or R14b is independently selected from H, alkoxy, acyl, heteroaryl, sulfonate, carbonate, cyano, ester, amide, halo, aryl, amino, alkylamino, C1-6 alkyl, C3-10 cycloalkyl, haloalkyl, aralkenyl, aralkynyl, hetaralkenyl, hetaralkynyl, and heterocyclyl;
• or two adjacent R14a and/or R14b groups combine to form a carbocyclic or heterocyclic ring including the atoms to which they are attached.