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 low background interference. Commonly employed in fluorescence microscopy and in vivo imaging for tracking cellular processes and monitoring molecular interactions. Suitable for staining membranes and lipophilic structures due to its cationic and lipophilic nature. Also applied in photodynamic therapy research and as a probe in mitochondrial imaging owing to its ability to accumulate in mitochondria. Stable under physiological conditions and compatible with live-cell imaging protocols.