U-104 is primarily used in research settings as a selective inhibitor of histone deacetylase 6 (HDAC6). Its ability to target HDAC6 makes it valuable in studying cellular processes such as protein degradation, cell motility, and the regulation of the cytoskeleton. Due to its role in modulating acetylation of α-tubulin and heat shock proteins, U-104 is employed in investigations related to neurodegenerative diseases, cancer, and inflammatory conditions. It has shown potential in preclinical models for enhancing the efficacy of other anticancer agents by promoting apoptosis and inhibiting tumor cell migration. Its application remains largely confined to laboratory research, where it serves as a tool compound for probing HDAC6-dependent pathways.