It is widely used as a fluorescent pH indicator in biological research, particularly for measuring intracellular pH levels in live cells. Its acetoxymethyl ester form allows it to easily penetrate cell membranes, where it is hydrolyzed by intracellular esterases to release the active dye. This dye exhibits pH-dependent fluorescence, making it valuable for studying cellular processes such as acid-base homeostasis, metabolic activity, and organelle function. It is commonly applied in microscopy, flow cytometry, and fluorescence-based assays to monitor pH changes in real-time. Its dual-emission properties enable ratiometric measurements, enhancing accuracy and reducing artifacts caused by variations in dye concentration or photobleaching.