Ionic oxide conductors of the BIMEVOX family are potentially interesting catalysts for selective oxidation of hydrocarbons in which the migration of lattice oxygen plays an important role. The catalytic performance in fixed bed reactor of Bi2Cu0.1V0.9O5.35 (BICUVOX) and Bi2Co0.1V0.9O5.35 (BICOVOX) in the oxidative dehydrodimerisation of propene has been studied. BICOVOX is more active and more selective to 1,5-hexadiene than BICUVOX but hexadiene is found at high temperature only. The characterisation of the catalysts before and after catalysis by XRD, TPD and TGA shows that this particular catalytic behaviour is related to their partial reduction. (C) 2004 Elsevier B.V. All rights reserved.