Fluorescent dye compounds of formula (I) are disclosed. These compounds are useful as they interact with organic compounds in a manner such that excitation with certain wavelengths of light results in fluorescent emission. Detection and/or monitoring of the fluorescence provides a means for the detection or quantification of organic compounds when bound to these fluorescent dye compounds. Formula (I), wherein: each of R, R' and R'' is a hydrogen atom, halogen atom or a straight or branched C.sub.1-20 alkyl, alkenyl or alkynl group optionally substituted with one or more halogen, hydroxyl, and/or oxy group; rings A, B and C optionally include one or more double bonds; rings B and C are optionally substituted with one or more halogen atoms.