The dimerization of alpha-methylstyrene (AMS) 1 over highly dispersed strongly acidic ion exchange resins based on Nafion((R)) and entrapped in a porous silica matrix has been investigated in the continuous liquid phase. Over these new catalysts the dimerization rate is independent of the choice of solvent, which highlights the increased accessibility of the acid sites. Depending upon the reaction conditions different dimerization products are obtained. Complete conversion is achieved even at very high space velocities.