The conversion of commercial heavy reformates under industrially relevant transalkylation conditions was studied over seven different acid zeolite catalysts with channel systems containing 10 MR, 12 MR, and 10 + 12 MR pores, by high-throughput experimentation (HTE). Zeolites were impregnated with seven different metals (Re, Pt, Mo, Ga, Ni, La, Bi). The reaction network for the global process was established, and the initial rates for primary reactions were estimated. It was found that zeolite pore size and geometry have a direct influence on dealkylation and transalkylation of the different alkyl groups. The ethyl and propyl dealkylation rate increases, while the rate of alkyl group transalkylation decreases as the zeolite pore dimensions decrease. A multizeolitic catalyst has been designed to optimize the dealkylation of ethyl and propyl aromatics while producing the transalkylation of tri- and tetramethylbenzene with toluene/benzene in order to maximize xylene yield when during the processing of heavy reformate. 2005 Elsevier Inc. All rights reserved.