Highly structured catalyst support pellets have been produced that possess multiple, but regiospecific and well-defined, pore geometries. Mesoporous silica pellets with controlled pore sizes have been synthesised using one type of pore template for the pellet core zone, whilst using a different type of template for the surrounding shell region. These materials offer the potential of adding precisely engineered diffusion barriers to the outside of structured catalyst supports, or providing different environments for pore structure-sensitive reactions in different parts of a catalyst pellet. The pore structures of the newly synthesised materials have been characterised using the recently introduced, integrated nitrogen sorption and mercury porosimetry technique. The data arising from the latter type of experiments on materials with cylindrical channels has been analysed using both the conventional BJH pore diameter technique, and also a new analysis method that can determine both the pore length distribution and interconnectivity. The transport properties of the new materials have also been assessed. (C) 2004 Elsevier Ltd. All rights reserved.