DRP1i27 dihydrochloride is a potent inhibitor of human Drp1 (dynamin-related protein 1). DRP1i27 dihydrochloride binds to the GTPase site of Drp1, with hydrogen bonds to Gln34 and Asp218. DRP1i27 dihydrochloride targets Drp1-mediated mitochondrial fission in cell line models and protects against simulated ischemia-reperfusion injury.