(S)-4CPG is primarily used in neuroscience research as a selective antagonist for group I metabotropic glutamate receptors (mGluRs). It helps in studying the role of these receptors in synaptic transmission and plasticity, which are critical for understanding learning and memory processes. Additionally, it is utilized in investigating neurological disorders such as epilepsy, anxiety, and Parkinson's disease, as mGluRs are implicated in these conditions. Its application extends to exploring potential therapeutic strategies by modulating glutamate signaling pathways.