In this work, thermal CVD from a melamine source produces two-dimensional carbon nitride films with high orientation. The diffraction pattern from a θ/2θ scan shows two peaks at 27.77° and 57.3°, corresponding respectively to the (001) and (002) orientations. The pole figure of (001) indicates that the carbon–nitrogen layer in the film is stacked parallel to the substrate with a mosaic spread of 8.0°. We use an in-plane scan to successfully measure the pattern of (hk0) diffractions excluding and diffractions. Most of the observed diffraction peaks can be identified with polymeric melon Miller indices.