Organic-organic heteroepitaxy using two rodlike aromatic molecules shows that p-sexiphenyl aligns predominantly parallel to an underlying uniaxially oriented alpha-sexithiophene film (see figure) although there is no lattice match of the two layers. The structure of both layers is determined and the results suggest that a simple transfer of the well-established models of inorganic epitaxy cannot explain the heterostructures formed here.