The electronic properties of molecular films are analysed with the consideration of the molecular orientation. The study demonstrates that surfaces of electroactive oligomeric molecular films can be classified analogously to the elemental surfaces by their intrinsic work functions. The intrinsic work function of molecular films is correlated with their ionisation energies; again, the behaviour is analogous to the correlation existing between the first ionisation energy of elements and the work function of the corresponding elemental surfaces. The proposed intrinsic work-function concept suggests that the mechanism for the energy-level alignment at the interfaces associated with molecular films is virtually controlled by work functions of materials brought into the contact. (c) 2012 Elsevier B.V. All rights reserved.