Used as a chromogenic substrate in enzymatic assays, particularly for detecting esterase and lipase activity. Upon hydrolysis by these enzymes, it releases 4-nitrophenol, which is yellow in color and can be easily measured spectrophotometrically at around 400–410 nm. This property makes it valuable in clinical diagnostics, biochemical research, and high-throughput screening to monitor enzyme kinetics and inhibition. It is also employed in microbiology for identifying specific bacterial enzyme profiles. Its stability and clear color change enhance its utility in both liquid and solid-phase assay systems.