UBCS039 is primarily used in research settings as a selective inhibitor of the G9a histone methyltransferase enzyme. This makes it a valuable tool in epigenetic studies, particularly in understanding gene silencing mechanisms associated with histone methylation. It has been applied in cellular assays to investigate the role of G9a in cancer progression, where its inhibition can lead to reactivation of tumor suppressor genes. UBCS039 is also utilized in stem cell research to modulate differentiation pathways by altering chromatin structure. Due to its specificity, it helps scientists dissect the functional outcomes of H3K9 methylation without broadly affecting other epigenetic marks. Its application remains confined to laboratory and preclinical studies, with no current use in clinical or industrial processes.