An understanding of the interfaces in molecular organic thin films is crucial to the advancement of organic devices. This thesis presents a comprehensive study of three similar organic molecules on three inorganic substrates using a variety of measurement techniques to gain a systematic insight into film growth and structure, electronic band structure and the energy level alignment of the interface. In Chapter 3, the growth and structure, both geometric and electronic, of rod-like organic molecules sexiphenyl (6P), sexithiophene (6T) and pentacene (5A) were studied on the TiO2(110), Cu(110) and Cu(110)-(2x1)O surfaces. The molecular axes in both monolayer and multilayer films are observed to align parallel to the protruding atomic rows. The templating abilities of these two-fold symmetric surfaces were then used to create ?single? crystalline films for controlled studies in later chapters. In Chapter 4, it was seen that oriented molecular films used as substrates impose their axial alignment on a second species. In Chapter 5, the electronic structure of ?single? crystal multilayer organic films was investigated. Perpendicular to the molecular axes, intermolecular dispersion was observed, while parallel to the molecular axes, discrete molecular orbitals were seen with a defined energy-momentum relationship, i.e. the intramolecular dispersion. It is shown that the photoemission intensity is excellently predicted by the Fourier transform of the initial state wavefunction of the molecular orbital. In Chapter 6, it is shown that both the highest occupied molecular orbital and the partially filled lowest ?unoccupied? molecular orbital retain their molecular character in the strongly bound 6P monolayer on Cu(110) and that both the Cu electronic structure and the periodicity of the two dimensional molecular overlayer are reflected in the photoemission measurements. Also, a significant intermolecular dispersion was observed in 5A monolayer and multilayer films on Cu-(2x1)O.