DCPIB is a selective, reversible and potent inhibitor of volume-regulated anion channels (VRAC). DCPIB voltage-dependently activates potassium channels TREK1 and TRAAK, and inhibits TRESK, TASK1 and TASK3 (IC50s: 0.14, 0.95, 50.72 μM, respectively). DCPIB is also a selective blocker of swelling-induced chloride current (ICl,swell), with an IC50 of 4.1 μM. DCPIB is a useful tool for investigating structure-function studies of K2P channels.