Used as a lipophilic fluorescent tracer for cell membrane labeling in biological imaging. Its near-infrared fluorescence allows deep tissue penetration and low background signal, making it ideal for in vivo imaging, cell tracking, and monitoring cell migration in animal models. Commonly applied in stem cell research, tumor biology, and developmental studies where long-term cell tracing is required. Also employed in membrane fusion assays and neuronal pathway tracing due to its strong retention in membranes and high photostability.