GSK-256066 is primarily utilized in research settings as a potent and selective inhibitor of phosphodiesterase 4 (PDE4). Its application is focused on studying the role of PDE4 in various biological processes, particularly in inflammatory and immune responses. Researchers use it to investigate potential therapeutic effects in conditions like chronic obstructive pulmonary disease (COPD), asthma, and other inflammatory disorders. Additionally, it serves as a tool compound to explore the signaling pathways involving cyclic AMP (cAMP), which plays a critical role in cellular regulation. Its high selectivity makes it valuable for understanding PDE4-specific mechanisms and developing targeted treatments.