Monoacylated mesitylene is an important precursor used in fine chemical industries In the present work, acylation of mesitylene was carried out using hierarchical ZSM-5 catalyst to prepare 2',4',6'-trimethyl acetophenone (monoacylated Mesitylene). The catalyst hierarchical ZSM-5 possessing three generations of micro-, meso-, and macroporosities was fabricated through a dual-template approach using tetrapropylammonium hydroxide (TPAOH) and poly(methyl methacrylate) (PMMA) latex particles as micropore and macropore templates, respectively. The catalyst is well characterized by XRD, FTIR and SEM. The liquid phase reactions were carried out in the temperature range of 30-50 #x00B0;C. The effect of various parameters such as mole ratio of reactants, catalyst loading, and temperature on the rates of reaction has been investigated. The result shows that the present process gives 100% selective towards the desired product, that is, 2',4',6'-trimethyl acetophenone, because hierarchical ZSM-5 allows faster diffusion of the products out of the catalyst provide an important increase in the activity and selectivity.