Keggin heteropolyacids, Supported oil solids of different nature and textural characteristics, were used in the reaction of anethole dimerization in order to obtain metanethole. The characterization by Fourier transform infrared spectroscopy showed that all catalysts present the Keggin Structure of the heteropolyanions without degradation. Besides, all the obtained solids have strong acidity, as determined by potentiornetric titration. The result,; of anethole conversion show that the activity of the catalysts is strongly dependent on the textural properties of the supports used to obtain the catalysts, particularly their mean pore size. (c) 2005 Elsevier B.V. All rights reserved.