(S)-(-)-1-Phenylpropylamine is primarily used as a chiral intermediate in the synthesis of various pharmaceuticals. Its stereospecific properties make it valuable in the production of enantiomerically pure compounds, which are crucial for drugs that require high specificity and efficacy. It is often employed in the development of active pharmaceutical ingredients (APIs) for central nervous system (CNS) drugs, including antidepressants and stimulants. Additionally, it serves as a building block in organic synthesis for creating complex molecules with potential therapeutic applications. Its role in asymmetric synthesis also aids in the preparation of agrochemicals and fine chemicals, where precise stereochemistry is essential for desired biological activity.