4-Nitrophenyl formate is used as a reagent in organic synthesis, particularly in esterification reactions for preparing esters and other derivatives. It serves as a key intermediate in the production of pharmaceuticals and agrochemicals. In analytical and biochemical chemistry, it is employed as a chromogenic substrate for assaying esterases and lipases, where hydrolysis releases 4-nitrophenolate, which exhibits pH-dependent color changes (yellow at basic pH) for spectrophotometric detection and as an indicator in enzymatic studies. Its nitro group makes it useful in investigations of electron transfer and redox reactions. Additionally, it finds application in the development of dyes and pigments due to its ability to form stable colored compounds.