Used primarily as a fluorescent probe in biological imaging due to its strong near-infrared emission and high photostability. It binds selectively to cellular membranes and is especially useful for tracking membrane dynamics and lipid raft formation in live cells. Its sulfonate and carboxylate groups enhance water solubility and reduce nonspecific binding, making it ideal for use in aqueous biological environments. Commonly employed in fluorescence microscopy, flow cytometry, and real-time cell imaging. Also utilized in photodynamic therapy research and as a labeling agent for biomolecules in diagnostic applications.