We report the fabrication of cubic laid mesoporous silica thin films via a new approach involving mesophase transformation induced by the degradation of organic moiety from the film during calcination. The mesoporous silica film is synthesized using tetraethyl orthosilicate (TEOS) as a silica source and a diblock copolymer (Brij-30) as a structure-directing agent under acidic conditions. Control of mesophase selection and its orientation in a mesoporous silica thin film appears to be possible by the induced phase transformation approach reported here. (c) 2005 Elsevier B.V. All rights reserved.