This compound is widely used as a substrate in biochemical assays to measure the activity of phosphatase enzymes. When phosphatases act on it, they cleave the phosphate group, releasing 4-nitrophenol, which is yellow and can be easily quantified using spectrophotometry at around 405 nm. This makes it a valuable tool in research and diagnostic labs for studying enzyme kinetics, screening inhibitors, and assessing phosphatase activity in various biological samples. Its stability and sensitivity contribute to its effectiveness in high-throughput screening and enzyme-linked assays.