Used as a fluorescent labeling reagent in bioconjugation and imaging applications. Its water-soluble structure allows efficient labeling of proteins, antibodies, or nucleic acids without requiring organic solvents. Commonly applied in flow cytometry, fluorescence microscopy, and gel electrophoresis to track biomolecules due to its strong absorption and emission in the visible range. The diacid functional groups enable stable amide bond formation with primary amines on biomolecules, making it suitable for preparing conjugates in biological assays.