The adsorption and electronic structure of benzene (C6H6) on thin film MgO(100)/Mo(100) and highly ordered Al2O3/Mo(110) substrates have been studied using temperature-programmed desorption (TPD) and high-resolution electron energy loss spectroscopy (HREELS). Three desorption states have been found for both surfaces. The first corresponds to adsorption of the aromatic ring plane parallel to the surface at low coverages (less than or equal to 1 ML). Intermediate coverages (>1 ML) give rise to a desorption at a slightly lower temperature, corresponding to the metastable, upright (end-on) adsorption of benzene on the monolayer-covered surface. Large exposures of benzene yield the multilayer with an anomalous higher temperature desorption sequence in the TPD. Both surfaces reveal spectroscopic windows by HREEL between the phonon modes and optical band gap transitions which allow identification of benzene electronic and vibronic transitions. This window is between 2.5 and 5.5 eV in MgO/Mo(100) and 2.5 and 6.7 eV in Al2O3/Mo(110). Even very low coverages of benzene on these surfaces show the singlet-to-singlet (1)E(1u) <-- (1)A(1g) transition. Higher coverages show the loss peaks assigned to B-3(1u) <-- (1)A(1g), B-1(2u) <-- (1)A(1g), and B-1(1u) <-- (1)A(1g) as well. Vibronic bands with 110 +/- 2 meV spacing in the loss region of 3.5-5.7 eV are observed. Diminishing vibronic band intensity and loss energy shifts at the lower coverages of benzene as well as TPD results indicate a weak interaction between benzene and Al2O3/Mo(110) or MgO/Mo(100). The influence of either substrate on the electronic transitions of benzene is weak with respect to the interaction of benzene with metal surfaces, e.g. Ag(111), even though TPD results show similar desorption temperatures.