Based on the formation of the ternary host-guest inclusion complex between veratryl alcohol, o-iodoxybenzoic acid (IBX) and cucurbit[8]uril (Q[8]), the effect of substrate substituents on the IBX oxidation of aryl alcohols to the corresponding aldehyde subject to supramolecular catalysis by (218] in aqueous solvent is described. Aryl alcohols with different substituent effect on electron, for example, 2,3,4-methoxybenzyl alcohols and 2,3,4-pyridinemethanol hydrochlorides, have been subjected to the procedure for IBX oxidizing in the absence and presence of 018] at room temperature. The catalytic ability of Q[8] reveals that the electronic effect of the substituent on the a-carbon of the aryl alcohol is crucial to the Q[8]-catalytic oxidation, and the supramolecular catalysis of Q[8] is mechanistically suggested to contribute to the alcohols with mainly negative inductive effect of substituent. (C) 2013 Elsevier B.V. All rights reserved.