The electronic structure of interfaces between aromatic adsorbates and metal oxide surfaces has been investigated using periodic hybrid ab initio Hartree-Fock-density functional theory calculations. Strong interfacial electronic coupling is observed for isonicotinic acid adsorbed on ZnO(1 0 1¯ 0) and TiO2(1 1 0) surfaces. The results are in good agreement with experiments of ultrafast surface electron transfer processes for TiO2, and current experimental controversies regarding ZnO are clarified theoretically. © 2002 Elsevier Science B.V. All rights reserved.