Monochlorobimane is widely used as a fluorescent probe for detecting and measuring glutathione levels in cells. It selectively binds to glutathione, forming a highly fluorescent adduct, which allows researchers to monitor glutathione concentration and distribution in live cells. This application is particularly valuable in studying oxidative stress, cellular detoxification processes, and the role of glutathione in various biological systems. Additionally, it is utilized in flow cytometry and fluorescence microscopy to assess cell viability and redox status. Its sensitivity and specificity make it a crucial tool in biochemistry and cell biology research.