CNx/TiNy bilayers have been prepared by ion beam sputtering. Transmission electron microscopy observation of the films shows that some crystals exhibiting a polyhedron-type shape contain cores. The crystal sizes range from 100 to 300nm. The results obtained by selected area electron diffraction reveal that the crystals belong to the cubic-C3N4 phase and their core is the Ti2N phase. Two types of heteroepitaxial matching between cubic-C3N4 and Ti2N are found in the CNx/TiNy bilayers, namely (1 1 2) cubic-C(3)N(4)parallel to (1 1 1 3) Ti2N and [4 2 (3) over bar] cubic-C(3)N(4)parallel to [1 (1) over bar 0] Ti2N. The heteroepitaxial lattice misfit of 5.78% is calculated by the Bramfitt's lattice misfit method.