Abstract: Novel chromophor derivatives of cyclic anhydrides are provided which have the ability to react with a variety of organic substrates forming adducts which are useful in analytical techniques for the detection and measurement of biological compounds.

Abstract: Novel chromophor derivatives of cyclic anhydrides are provided which have the ability to react with a variety of organic substrates forming adducts which are useful in analytical techniques for the detection and measurement of biological compounds.

Abstract: Novel urea derivatives of oxazine and thiazine chromophors have the structural formula I or II. ##STR1## wherein M is oxygen or sulfur, R.sub.1 and R.sub.2 are aliphatic alkyl groups or hydrogen; R.sub.3 is hydrogen or alkyl group; R.sub.4 is hydrogen, alkyl or amine group; R.sub.5 is hydrogen, amine or alkyl group; X.sup..crclbar. is an anion consisting of an organic (e.g. CH.sub.3 COO.sup..crclbar., CH.sub.3 CH.sub.2 COO.sup..crclbar. and the like) or inorganic specie (e.g. Cl.sup..crclbar., Br.sup..crclbar., I.sup..crclbar., ClO.sub.4.sup..crclbar., SO.sub.4 ", and the like); n is 0 to 20; Z is N.dbd.C.dbd.O, N.dbd.C.dbd.S, carboxylic, primary or secondary amine, and when n=0, Z may be ##STR2## wherein Q is hydroxyl, amino, carboxylic, sulfydryl, isocyanato, or isothiocyanato.The functional oxazine-urea and thiazine-urea derivatives react with compounds of interest to form adducts resulting in the fluorescent labeling of the compound.