Used as a near-infrared (NIR) fluorescent dye in bioimaging and optical imaging applications. Its strong absorption and emission in the NIR region make it suitable for deep tissue imaging due to reduced autofluorescence and improved light penetration. Commonly employed in fluorescence microscopy, in vivo imaging, and as a labeling agent for biomolecules. Also utilized in photodynamic therapy and as a sensor in optoelectronic devices. Its chloride salt form enhances solubility and stability in aqueous and polar environments, facilitating use in biological systems.