Zr-SBA-15 materials were synthesized and the activity of the catalysts was investigated in the alkylation of aromatics with benzyl chloride. While Zr-SBA-15 materials needed more than 12h of reaction to achieve quantitative conversion, an unusually high catalytic activity was observed for reused materials that provided quantitative conversions of starting material in less than 1h. This dramatic increase in activity observed for reused and/or treated Zr-SBA-15 in the alkylation of aromatics with benzyl chloride points to the formation of novel highly acidic Lewis Cl x Zr–O–Si species on the catalyst surface.