A cell-permeable pyridinyloxypyridine compound that acts as a potent and highly selective inhibitor against TGFβ RI/ALK5 (IC50 = 72 nM, [ATP] = 1 mM) by targeting both the ATP-binding site and the selectivity pocket, while exhibiting much reduced or little activity against a panel of 75 other kinases (IC50 <1μM).