Poly[3,4-(ethylenedioxy)thiophene] (PEDOT) encapsulated inside the faujasite micropores has been prepared by polymerization of the monomer in partially Fe-exchanged faujasites. Faujasites containing PEDOT within the interior exhibit notable electrical conductivity compared to plain faujasite. This conductivity is attributed to the presence of polarons that have been detected by EPR spectroscopy. (c) 2005 Elsevier B.V. All rights reserved.