BI-78D3 is primarily utilized in biochemical research due to its role as a selective inhibitor of JNK (c-Jun N-terminal kinase). Its application is significant in studying cellular signaling pathways, particularly those involved in stress responses, apoptosis, and inflammation. Researchers use it to investigate the mechanisms of diseases such as neurodegenerative disorders, cancer, and autoimmune conditions. By inhibiting JNK activity, BI-78D3 helps in understanding the protein's function and its potential as a therapeutic target. Additionally, it is employed in drug discovery processes to evaluate the efficacy of new compounds targeting JNK-related pathways.