Used as a fluorescent probe in biological imaging due to its strong near-infrared emission and high photostability. It features a carboxypentyl group for covalent conjugation to biomolecules such as antibodies or ligands, enabling specific labeling. The sulfonate groups enhance water solubility and reduce nonspecific binding, improving signal clarity in complex biological environments. It can also interact with proteins and cellular membranes for non-specific applications. Suitable for live-cell imaging and real-time tracking of biomolecules. Commonly employed in fluorescence microscopy and flow cytometry for detecting cellular processes and molecular interactions. Also utilized in diagnostic assays requiring sensitive detection, especially in deep-tissue imaging applications.