ML204 is a novel and potential TRPC4 Channel inhibitor. ML204 inhibited TRPC4β-mediated intracellular Ca(2+) rise with an IC(50) value of 0.96 μm and exhibited 19-fold selectivity against muscarinic receptor-coupled TRPC6 channel activation. ML204 represents an excellent novel tool for investigation of TRPC4 channel function and may facilitate the development of therapeutics targeted to TRPC4.