Interfacial electronic structures and photoemission spectral characteristics of Ca/MEH–PPV/Au were studied by one and two photon photoemission spectroscopy. For a pristine MEH–PPV film, the work function was measured to be 4.0 eV. This value is 1.1 eV lower than that of a bare Au substrate. At a Ca coverage of 3 Å, the work function was sharply decreased to 2.6 eV. Upon further deposition, it was decreased to 2.3 eV, which is 0.6 eV lower than that of metallic Ca. CaO formation was revealed at the interface of Ca and MEH–PPV.