An energy transfer dye comprising a donor dye covalently attached to an acceptor dye, wherein the donor dye is capable of absorbing light at a first wavelength and emitting excitation energy in response, the acceptor dye is capable of absorbing the excitation energy emitted by the donor dye and fluorescing at a second wavelength in response, and the donor dye is a compound selected from the group consisting of structures,, and wherein: each of R 1 -R 3 and R 6 -R 16 is independently selected from the group consisting of -H, halogen, aryl, substituted aryl, heteroaryl, -CO 2 H, -CO 2 R, -SO 3 H, -SO 3 R, -CH 2 CO 2 H, -CH 2 CO 2 R, -CH 2 SO 3 H, -CH 2 SO 3 R, -CH 2 NH 2, -CH 2 NHR, -NO 2, C 1 -C 6 alkyl, substituted C 1 -C 6 alkyl, C 1 -C 6 alkoxy, substituted C 1 -C 6 alkoxy, C 1 -C 6 alkoxyaryl, substituted C 1 -C 6 alkoxyaryl, biphenyl, substituted biphenyl, benzyl, substituted benzyl, benzoyl, and substituted benzoyl, wherein R is selected from C 1 -C 6 alkyl, substituted C 1 -C 6 alkyl, C 1 -C 6 alkoxy, substituted C 1 -C 6 alkoxy, C 1 -C 6 alkoxyaryl, substituted C 1 -C 6 alkoxyaryl, phenyl, substituted phenyl, biphenyl, substituted biphenyl, benzyl, substituted benzyl, benzoyl, substituted benzoyl, and a linking group; and each of R 4 and R 5 taken separately is selected from the group consisting of C 1 -C 6 alkyl and C 1 -C 6 substituted alkyl, R 4 and R 5 taken together are selected from the group consisting of C 3 -C 7 cycloalkyl, C 4 -C 7 unsaturated cycloalkyl, C 3 -C 7 substituted cycloalkyl and C 4 -C 7 substituted unsaturated cycloalkyl, wherein at least one of R 1 -R 3 and R 6 -R 16 is -SO 3 H, with the proviso that if the compound comprises the structure, then at least one of R 1. R 2, R 3 or R 8 is independently selected from the group consisting of halogen, aryl, substituted aryl, heteroaryl, -CO 2 H, -CO 2 R, -SO 3 H, -SO 3 R, -CH 2 CO 2 H, -CH 2 CO 2 R, -CH 2 SO 3 H, -CH 2 SO 3 R, -CH 2 NH 2, -CH 2 NHR, -NO 2, C 1 -C 6 alkyl, substituted C 1 -C 6 alkyl, C 1 -C 6 alkoxy, substituted C 1 -C 6 alkoxy, C 1 -C 6 alkoxyaryl, substituted C 1 -C 6 alkoxyaryl,, biphenyl, substituted biphenyl, benzyl, substituted benzyl, benzoyl, and substituted benzoyl, wherein R is selected from the group consisting of C 1 -C 6 alkyl, substituted C 1 -C 6 alkyl, C 1 -C 6 alkoxy, substituted C 1 -C 6 alkoxy, C 1 -C 6 alkoxyaryl, substituted C 1 -C 6 alkoxyaryl, phenyl, substituted phenyl, biphenyl, substituted biphenyl, benzyl, substituted benzyl, benzoyl, substituted benzoyl, and a linking group. each of R 1 -R 3 and R 6 -R 16 is independently selected from the group consisting of -H, halogen, aryl, substituted aryl, heteroaryl, -CO 2 H, -CO 2 R, -SO 3 H, -SO 3 R, -CH 2 CO 2 H, -CH 2 CO 2 R, -CH 2 SO 3 H, -CH 2 SO 3 R, -CH 2 NH 2, -CH 2 NHR, -NO 2, C 1 -C 6 alkyl, substituted C 1 -C 6 alkyl, C 1 -C 6 alkoxy, substituted C 1 -C 6 alkoxy, C 1 -C 6 alkoxyaryl, substituted C 1 -C 6 alkoxyaryl, biphenyl, substituted biphenyl, benzyl, substituted benzyl, benzoyl, and substituted benzoyl, wherein R is selected from C 1 -C 6 alkyl, substituted C 1 -C 6 alkyl, C 1 -C 6 alkoxy, substituted C 1 -C 6 alkoxy, C 1 -C 6 alkoxyaryl, substituted C 1 -C 6 alkoxyaryl, phenyl, substituted phenyl, biphenyl, substituted biphenyl, benzyl, substituted benzyl, benzoyl, substituted benzoyl, and a linking group; and each of R 4 and R 5 taken separately is selected from the group consisting of C 1 -C 6 alkyl and C 1 -C 6 substituted alkyl, R 4 and R 5 taken together are selected from the group consisting of C 3 -C 7 cycloalkyl, C 4 -C 7 unsaturated cycloalkyl, C 3 -C 7 substituted cycloalkyl and C 4 -C 7 substituted unsaturated cycloalkyl, wherein at least one of R 1 -R 3 and R 6 -R 16 is -SO 3 H, with the proviso that if the compound comprises the structure, then at least one of R 1. R 2, R 3 or R 8 is independently selected from the group consisting of halogen, aryl, substituted aryl, heteroaryl, -CO 2 H, -CO 2 R, -SO 3 H, -SO 3 R, -CH 2 CO 2 H, -CH 2 CO 2 R, -CH 2 SO 3 H, -CH 2 SO 3 R, -CH 2 NH 2, -CH 2 NHR, -NO 2, C 1 -C 6 alkyl, substituted C 1 -C 6 alkyl, C 1 -C 6 alkoxy, substituted C 1 -C 6 alkoxy, C 1 -C 6 alkoxyaryl, substituted C 1 -C 6 alkoxyaryl,, biphenyl, substituted biphenyl, benzyl, substituted benzyl, benzoyl, and substituted benzoyl, wherein R is selected from the group consisting of C 1 -C 6 alkyl, substituted C 1 -C 6 alkyl, C 1 -C 6 alkoxy, substituted C 1 -C 6 alkoxy, C 1 -C 6 alkoxyaryl, substituted C 1 -C 6 alkoxyaryl, phenyl, substituted phenyl, biphenyl, substituted biphenyl, benzyl, substituted benzyl, benzoyl, substituted benzoyl, and a linking group.