This paper describes the detection of volatile organic compounds (VOCs) through analyses of two output signals from integrated microcantilever sensor arrays coated with organic-inorganic hybrid sensing layers. The surface of TiO2 porous films was modified by amphiphilic terthiophene monomers and the adsorbed monomers were polymerized at the surface of TiO2 nanoparticles. The TiO2 porous films covered with polythiophene layers worked as highly sensitive sensing interfaces to provide two output signals for weight and resistance changes during exposure to VOC vapor. When the TiO2 porous films onto the sensor arrays were dyed with various kinds of amphiphilic monomers with different substituents, the resulting films provide exact information on VOC concentration from the mass changes as well as VOC classification from the analyses of response patterns.