The multifunctional properties of modified cyclodextrins (CDs) in a palladium–charcoal catalyzed Heck reaction have been investigated. Contrary to native CDs, the methylated CDs induced a significant increase in chemo- and stereoselectivities in the C–C coupling between aryl iodides and acrylate derivatives. These results were rationalized by considering that the key parameter is the adsorption of the cyclodextrin on the catalytic solid and not the solubilisation of the substrate into the aqueous phase by cyclodextrin.