Abstract: A compound of formula (I) is described in which each A, which may be the same or different, is a halide selected from fluoride, chloride, bromide and iodide, or is O—Y, wherein Y is a substituted or unsubstituted, saturated or unsaturated, straight or branched chain alkyl moiety. R1, R2, R3, R6, R7, and R8 are each independently H, OH, NO2 or O-L-X, wherein L is a spacer group, and X is a conjugation group or a water-solubilizing group. At least one of R1, R2, R3 is OH or O-L-X and at least one of R6, R7, and R8 is OH or O-L-X. R4 and R5, which may be the same or different, are each independently H; or are a substituted or unsubstituted, saturated or unsaturated, cyclic moiety; a substituted or unsubstituted, saturated or unsaturated heterocyclic moiety; or a substituted or unsubstituted, saturated or unsaturated, straight or branched chain alkyl moiety. Also described are dye conjugates comprising a compound of the invention.