Used primarily in peptide synthesis as an activated ester of Nα-benzyloxycarbonyl-L-lysine, it facilitates the formation of peptide bonds by providing a good leaving group (p-nitrophenolate), ensuring selective incorporation of lysine residues and enhancing the efficiency and accuracy of the synthesis process. Additionally, it serves as a chromogenic substrate in biochemical research to assay the activity of lysine-specific proteases, such as trypsin, through the spectrophotometric detection of the yellow p-nitrophenol released upon hydrolysis. This application provides insights into enzyme mechanisms, protein interactions, and molecular function. Its stability and reactivity make it a valuable tool in organic chemistry laboratories for constructing complex molecular structures and in pharmaceutical research.