The reaction of cinnamonitrile [PhCH = CHCN] with arenes in the superacid TfOH at room temperature for 1 h gave two types of compounds, 3-aryl-3-phenyl propionitriles [Ar(Ph)CHCH ₂ CN] and/or 3-phenylindanones in 28–76% yield. The formation of these two reaction products depends on the nucleophilicity of the arene. In these reactions, carbocations generated upon the protonation of cinnamonitrile in TfOH behave as bi-centered electrophiles possessing reactive centers on the C3 carbon of the double bond and on the C1 carbon of the nitrile group.