(R)-(-)-Phenylsuccinic acid is primarily used in the field of organic synthesis and pharmaceutical research. It serves as a chiral building block for the production of various optically active compounds, which are essential in the development of enantiomerically pure drugs. Its chiral nature makes it valuable in asymmetric synthesis, where it can be used to induce stereoselectivity in chemical reactions. Additionally, it is employed in the synthesis of complex molecules, including natural products and bioactive compounds, where the specific stereochemistry is crucial for biological activity. In material science, it can be utilized to create chiral polymers or as a precursor for specialty chemicals with specific optical properties. Its applications also extend to analytical chemistry, where it may be used as a standard or reagent in chiral separation techniques.