A-366 is primarily used in epigenetic research as a potent and selective inhibitor of the G9a histone methyltransferase enzyme. This compound effectively reduces histone H3 lysine 9 dimethylation (H3K9me2), a mark associated with gene silencing, making it a valuable tool for studying chromatin dynamics and gene expression regulation. Due to its high selectivity and cellular permeability, A-366 is widely applied in cellular assays to probe the biological roles of G9a in processes such as cancer progression, stem cell differentiation, and viral latency. It has shown potential in preclinical studies for reactivating silenced tumor suppressor genes, suggesting possible utility in cancer therapy development. Additionally, A-366 is used in combination with other epigenetic modulators to investigate synergistic effects on reprogramming gene networks.