Liquid phase acylation of benzene by acyl chloride (e.g., benzoyl chloride, butyryl chloride or phenyl acetyl chloride) over InCl3, GaCl3 and ZnCl2 supported on commercial clays (viz. montmorillonite-K10, montmorillonite-KSF and kaolin) or high silica mesoporous MCM-41 at 80 degrees C has been investigated. The Mont.-K10 and Si-MCM-41 supported InCl3 and GaCl3 catalysts showed high activity in the acyation of benzene by benzoyl chloride even in the presence of moisture in the reaction mixture. The redox function of the supported InCl3, GaCl3 or ZnCl2 catalysts seems to play a very important role in the acylation process.