Methyl phenyl sulfoxide is primarily used in organic synthesis as an intermediate for the production of various pharmaceuticals and agrochemicals. It serves as a chiral auxiliary in asymmetric synthesis, enabling the creation of enantiomerically pure compounds, which are crucial in drug development. Additionally, it is employed in the synthesis of sulfoxides and sulfones, which are important in the manufacture of polymers and specialty chemicals. Its role as a solvent or catalyst in certain chemical reactions also makes it valuable in research and industrial processes.