7-Ethoxy-4-(trifluoromethyl)coumarin is primarily used as a fluorescent probe in biochemical and cellular studies. Its strong fluorescence properties make it valuable for labeling and tracking molecules in various biological systems. It is often employed in enzyme activity assays, particularly for detecting esterase and lipase activities, where the cleavage of the ethoxy group results in a measurable fluorescence change. Additionally, it is utilized in imaging techniques to study intracellular processes and monitor dynamic changes in live cells. Its stability and sensitivity also make it suitable for use in high-throughput screening and diagnostic applications.