2,4,5-Triarylimidazoles could be obtained in excellent yields by the one-pot three-component condensation of benzil/benzoin,aldehydes and ammonium acetate in the presence of catalytic amount of the inexpensive, readily available and non-toxic ceric (IV) ammonium nitrate (CAN) in aqueous media under ultrasound at room temperature. In this reaction the products were obtained in short reaction time and easy operation under mild conditions.