Abstract: The present invention relates to compounds useful for measuring aromatase activity. The invention further provides methods for measuring aromatase activity and for screening test agents which modulate aromatase activity. A kit is also provided for use in such screening methods.

Abstract: Disclosed are cyanine dyes that are useful for labelling and detecting biological and other materials. The dyes are of formula (I): in which at least one of groups R1, R2, R3, R4, R5, R6, R7, R8, R9, R10 R11, R12, R13 and R14 is -L-M or -L-P, where L is a linking group, M is a target bonding group and P is a conjugated component, and at least one of groups R3, R4, R5, R6, R7, R8, R9 and R10 comprises fluorine. The use of cyanine dyes substituted by fluorine and having additional substitution with three or more sulphonic acid groups for labelling biological target molecules results in a labelled product in which there is reduced dye-dye aggregation and improved photostability, compared with cyanine dyes having no such substitutions.