EI1 is primarily used in research settings as a potent and selective inhibitor of EZH2, an enzyme involved in histone methylation. By inhibiting EZH2, EI1 helps in studying the role of this enzyme in various biological processes, particularly in cancer research. It is utilized to understand the mechanisms of EZH2 in tumorigenesis and to explore potential therapeutic strategies for cancers where EZH2 is overexpressed or mutated. Additionally, EI1 is employed in epigenetic studies to investigate the impact of histone modification on gene expression and cellular differentiation. Its application extends to drug discovery, where it serves as a tool compound for developing new EZH2-targeting therapies.