Abstract: The present invention describes xanthene dyes, including rhodamines, rhodols and fluoresceins that are substituted one or more times by a sulfonic acid or a salt of a sulfonic acid. The dyes of the invention, including chemically reactive dyes and dye-conjugates are useful as fluorescent probes, particularly in biological samples.

Abstract: The present invention relates to a family of cyanine dyes possessing lipophilic alkyl chains and either one or more reactive functional groups, bromo or chloro, or phenyl, sulfophenyl or polysulfophenyl substituents or combinations thereof. The dyes of the invention are useful for staining membranes in cells or isolated from cells, and are well-retained therein. Additionally, the reactive dyes of the invention are useful for preparing dye-conjugates, thereby conferring the membrane staining ability of the subject dye onto the resulting dye-conjugate.

Abstract: The present invention describes 7-aminocoumarin dyes that are substituted one or more times at the 3-, 6- and/or 8-positions by a sulfonic acid or a salt of a sulfonic acid, said dyes being useful as fluorescent probes or in the preparation of enzyme substrates, caged probes, or adducts with reducing sugars. The dyes of the invention optionally possess a reactive group useful for preparing fluorescent conjugates, which conjugates and methods for their preparation are described herein.