Used as a near-infrared fluorescent dye in biological imaging and labeling applications. Exhibits strong absorption and emission in the NIR region, allowing deep tissue penetration with minimal autofluorescence and light scattering. Commonly employed in fluorescence microscopy and in vivo imaging for tracking cellular processes and monitoring biomolecules. Also utilized in photodynamic therapy and as a photosensitizer in light-driven applications due to its efficient light absorption and stability under irradiation.