Phenyl methanesulfonate is primarily used as an alkylating agent in organic synthesis, where it introduces the phenyl group into various molecules. It is particularly valuable in the pharmaceutical industry for the modification of active pharmaceutical ingredients (APIs) to enhance their efficacy or stability. Additionally, it serves as a reagent in the preparation of intermediates for dyes, agrochemicals, and other fine chemicals. Its role in cross-coupling reactions also makes it useful in the development of complex organic compounds. In research, it is employed to study reaction mechanisms involving sulfonate esters.