Use of a dye for the determination of protein melt temperature, the dye being of formula: wherein: R 1 to R 6 is independently selected from the group consisting of: hydrogen, halogen, - (CH 2) n CO 2 H (wherein n = 0 to 6), -(CH 2) n CO 2 R (wherein n = 0 to 6), cycloakyl, alkyl (1-5 carbons), aryl, heteroaryl, arylalkyl (wherein the alkyl portion is 1-5 carbon atoms), alkenyl, azido, alkynyl, and sulfo, alone or in combination, wherein o, m and p are independently selected from the group consisting of: hydrogen, halogen, -(CH 2) n CO 2 H (wherein n = 0 to 6), -(CH 2) n CO 2 R (wherein n = 0 to 6), cycloakyl, alkyl (1-5 carbons), aryl, heteroaryl, arylalkyl (wherein the alkyl portion is 1-5 carbon atoms), alkenyl, azido, alkynyl, and sulfo, alone or in combination, wherein an alkenyl substituent is substituted or unsubstituted, wherein the alkenyl group is ethenyl, dienyl, or trienyl, wherein the one or more substituents for an alkenyl group is selected from the group consisting of: hydrogen, halogen, alkyl (1-5 carbon atoms), cyano, carboxylate ester, carboxamide, aryl, heteroaryl, and any combination thereof, wherein an aryl is selected from phenyl, 1-naphthyl, 2-naphthyl, 1-pyrenyl, 9-anthryl, pyridyl, quinolyl, and alkoxy derivatives thereof, wherein an aryl or heteroaryl group is substituted or unsubstituted, wherein the one or more substituents for an aryl or heteroaryl group is selected from the group consisting of: hydrogen, halogen, -(CH 2) n CO 2 H (wherein n = 0 to 6), -(CH 2) n CO 2 R (wherein n = 0 to 6) alkyl (1-5 carbons), alkoxy(wherein the alkyl portion is 1-4 carbon atoms), and any combination thereof, wherein any alkyl or arylalkyl group is substituted or unsubstituted, wherein the one or more substituents for an alkyl or arylalkyl group is selected from the group consisting of: hydrogen, halogen, -(CH 2) n CO 2 H (wherein n = 0 to 6), -(CH 2) n CO 2 R (wherein n = 0 to 6), cycloakyl, alkyl (1-5 carbons), aryl, heteroaryl, arylalkyl (wherein the alkyl portion is 1-5 carbon atoms), alkenyl, azido, alkynyl, and sulfo, alone or in combination, wherein the alkyl group in any substituent of an aryl group may be further substituted by an ester or amide substituent, and wherein L x is a linker, where x = 0 to 6, and wherein the linker may be selected from alkyl (1-6 carbons), and heteroalkyl, (1-6 atoms). R 1 to R 6 is independently selected from the group consisting of: hydrogen, halogen, - (CH 2) n CO 2 H (wherein n = 0 to 6), -(CH 2) n CO 2 R (wherein n = 0 to 6), cycloakyl, alkyl (1-5 carbons), aryl, heteroaryl, arylalkyl (wherein the alkyl portion is 1-5 carbon atoms), alkenyl, azido, alkynyl, and sulfo, alone or in combination, wherein o, m and p are independently selected from the group consisting of: hydrogen, halogen, -(CH 2) n CO 2 H (wherein n = 0 to 6), -(CH 2) n CO 2 R (wherein n = 0 to 6), cycloakyl, alkyl (1-5 carbons), aryl, heteroaryl, arylalkyl (wherein the alkyl portion is 1-5 carbon atoms), alkenyl, azido, alkynyl, and sulfo, alone or in combination, wherein an alkenyl substituent is substituted or unsubstituted, wherein the alkenyl group is ethenyl, dienyl, or trienyl, wherein the one or more substituents for an alkenyl group is selected from the group consisting of: hydrogen, halogen, alkyl (1-5 carbon atoms), cyano, carboxylate ester, carboxamide, aryl, heteroaryl, and any combination thereof, wherein an aryl is selected from phenyl, 1-naphthyl, 2-naphthyl, 1-pyrenyl, 9-anthryl, pyridyl, quinolyl, and alkoxy derivatives thereof, wherein an aryl or heteroaryl group is substituted or unsubstituted, wherein the one or more substituents for an aryl or heteroaryl group is selected from the group consisting of: hydrogen, halogen, -(CH 2) n CO 2 H (wherein n = 0 to 6), -(CH 2) n CO 2 R (wherein n = 0 to 6) alkyl (1-5 carbons), alkoxy(wherein the alkyl portion is 1-4 carbon atoms), and any combination thereof, wherein any alkyl or arylalkyl group is substituted or unsubstituted, wherein the one or more substituents for an alkyl or arylalkyl group is selected from the group consisting of: hydrogen, halogen, -(CH 2) n CO 2 H (wherein n = 0 to 6), -(CH 2) n CO 2 R (wherein n = 0 to 6), cycloakyl, alkyl (1-5 carbons), aryl, heteroaryl, arylalkyl (wherein the alkyl portion is 1-5 carbon atoms), alkenyl, azido, alkynyl, and sulfo, alone or in combination, wherein the alkyl group in any substituent of an aryl group may be further substituted by an ester or amide substituent, and wherein L x is a linker, where x = 0 to 6, and wherein the linker may be selected from alkyl (1-6 carbons), and heteroalkyl, (1-6 atoms).