The control of pore diameter and topology of zeolites, as well as the nature of active sites and adsorption properties, allow in many cases the a priori design of catalysts for applications in the fields of oil refining, petrochemistry, and the production of chemicals and fine chemicals. The potentiality of nanocrystalline, delaminated, or ultralarge pore catalysts and of zeolites formed by channels with different dimensions is outlined. (C) 2003 Elsevier Science (USA). All rights reserved.