Used primarily as a fluorescent probe for cell labeling and tracking. It readily penetrates cell membranes and is hydrolyzed by intracellular esterases to yield a fluorescent product that is retained within live cells. This makes it ideal for monitoring cell proliferation, viability, and migration in both in vitro and in vivo studies. Commonly applied in immunology and cancer research to trace lymphocyte movement and tumor cell behavior. Also employed in assays involving phagocytosis and cell adhesion due to its stable and bright green fluorescence.