PDHK-IN-4 (Compound 30) is a potent inhibitor of PDHK with IC50s of 0.0051 and 0.0122 μM for PDHK2 and PDHK4, repectively. Pyruvate dehydrogenase kinases (PDHKs) are fascinating agent targets for numerous diseases, including diabetes and cancers. PDHK-IN-4 has the potential for the research of cancer diseases[1].