Used as a substrate in enzymatic assays, particularly for measuring alkaline phosphatase activity in biochemical and clinical diagnostics. Hydrolysis by the enzyme produces phenol and inorganic phosphate, enabling the detection and quantification of enzyme activity through colorimetric (e.g., via phenol or phosphate determination) or fluorometric methods. Commonly applied in immunoassays, such as ELISA, where alkaline phosphatase-conjugated antibodies generate a detectable signal. Also utilized in molecular biology for nucleic acid detection when used with phosphatase-labeled probes. Its stability and sensitivity make it suitable for research, diagnostic kits, and high-throughput screening.