PI-1840 is primarily utilized in biochemical research as a selective inhibitor of casein kinase 1 (CK1). Its application is significant in studies focused on understanding the role of CK1 in various cellular processes, including circadian rhythms, Wnt signaling, and DNA repair. Researchers employ PI-1840 to investigate the effects of CK1 inhibition on these pathways, providing insights into potential therapeutic targets for diseases such as cancer, neurodegenerative disorders, and metabolic syndromes. Additionally, PI-1840 is used in pharmacological studies to explore its efficacy and specificity in modulating CK1 activity, aiding in the development of novel drugs targeting CK1-related pathways.