This chemical is widely used as a fluorescent probe in biological research, particularly for measuring intracellular pH levels. Its acetoxymethyl ester form allows it to passively diffuse into cells, where it is cleaved by intracellular esterases to release the fluorescent dye. This dye is sensitive to pH changes, making it valuable for studying cellular processes that involve pH fluctuations, such as endocytosis, exocytosis, and lysosomal activity. It is also employed in live-cell imaging and flow cytometry to monitor real-time pH dynamics in various cell types. Additionally, its carboxylate groups enable it to be conjugated with other molecules, expanding its utility in targeted imaging and diagnostic applications.