Solvent-vapor annealing was used to increase the field-effect mobility of soluble triethylsilylethynyl anthradithiophene spin-coated on organosilane-terminated silicon dioxide, yielding a high value of 1.2 cm(2) V (1) s (1). The cause of improvement was investigated by atomic force microscopy, X-ray diffraction, and near-edge X-ray absorption fine structure spectroscopy. Vapor annealing exerts little effect on the molecular tilt and the crystallinity normal to the surface, but improves the film morphology significantly, yielding larger grains with perhaps better in-plane crystallinity. (C) 2010 Elsevier B. V. All rights reserved.