(S)-(-)-Phenylsuccinic Acid is primarily utilized in the field of organic synthesis as a chiral building block. Its enantiomeric purity makes it valuable for the preparation of pharmaceuticals, particularly in the synthesis of active pharmaceutical ingredients (APIs) where stereochemistry plays a critical role in drug efficacy and safety. It is also employed in the development of asymmetric catalysts and ligands, which are essential in enantioselective reactions. Additionally, this compound finds applications in research and development for studying chiral recognition and separation processes in chromatography. Its role in fine chemical manufacturing further highlights its importance in producing high-purity, specialized compounds for various industries.