Arenesulfonic modified mesostructured SBA-15 is shown as an active catalyst for acylation of aromatic compounds using acetic anhydride as acylating agent. Arenesulfonic acid-centers anchored on the pore surface of a mesostructured SBA-15 material show a greater activity (normalised on the concentration of sulfonic groups) as compared to other homogeneous and heterogeneous sulfonated catalysts and even in solventless conditions. This high activity is accompanied with a remarkable thermal stability of the acid centers, without leaching of sulfur species during the reaction. Moreover, an increase of the amount of arenesulfonic centres does not modify the activity of the material per acid center. Thus, this work introduces a new application of these sulfonated mesostructured materials, not described in literature up to now.