PDHK-IN-5 (Compound 19) is a potent inhibitor of PDHK with IC 50 s of 0.006 and 0.0329 μM for PDHK2 and PDHK4, repectively. Pyruvate dehydrogenase kinases (PDHKs) are fascinating agent targets for numerous diseases, including diabetes and cancers. PDHK-IN-5 has the potential for the research of cancer diseases.