5(6)-Carboxyfluorescein diacetate is widely used as a fluorescent tracer in biological and medical research. It is particularly valuable for studying cell viability, membrane integrity, and intracellular enzyme activity. Once inside cells, it is hydrolyzed by esterases to produce carboxyfluorescein, which emits strong fluorescence, making it useful for tracking cell movement and proliferation. It is also employed in flow cytometry and fluorescence microscopy to monitor cell populations and assess cellular health. Additionally, it serves as a pH-sensitive probe in various experimental setups, helping researchers understand cellular environments and metabolic processes. Its non-toxic nature and high sensitivity make it a preferred choice for live-cell imaging and diagnostic applications.