Organic molecular beam deposition (OMBD) enables the fabrication of organic materials with controlled and reproducible electronic and optical properties. For electronic and photonic applications of organic materials, poly- and oligothiophenes are among the most interesting. Here the growth of highly oriented films of beta-tetrahexylsexithiophene by OMBD onto an organic ionic crystal substrate is reported. Analysis of UV-vis absorption spectra demonstrates a clear relationship between the ordered structure of the film and the crystal lattice of the substrate.