Used as a fluorescent probe in biochemical and cellular imaging due to its strong photostability and red-emitting fluorescence. It is particularly effective in labeling membranes and tracking lipid dynamics in live cells. Its carboxyl group allows for covalent conjugation to proteins, peptides, or other biomolecules, making it valuable in immunoassays and receptor labeling. Commonly employed in flow cytometry and confocal microscopy for high-resolution visualization of cellular structures.