A facile method for the synthesis of 1, 3, 5-triarylbenzenes is developed via cyclotrimerization of acetophenones in the presence of 4-dodecylbenzenesulfonic acid (DBSA) as an efficient Bronsted acid catalyst under solvent-free conditions. This synthetic protocol has several advantages such as green reaction conditions, short reaction times, high atom economy and good to excellent yields of the target products.