A different processing route to bimetallic oxynitrides has been developed using oxide precursors generated from coprecipitation of ethanolic solutions of the relevant metal chlorides. The nitridation of the mixed-metal precursors yields nanocrystalline oxynitrides. Representative group 5-group 6 transition metal oxynitrides, M1-x M'(x) (O,N) (M = Nb, Ta; M'= Mo, W) have been prepared and characterised by powder X-ray diffraction (PXD), scanning electron microscopy with energy dispersive analysis by X-rays (SEM/EDAX), transmission electron microscopy (TEM) with selected area electron diffraction (SAED), BET surface area measurements and SQUID magnetometry. The mixed-metal oxynitrides form rock salt structures (a similar to 4.3 angstrom) with disordered distributions of both cations and anions. The purity, particle size and surface area of materials are significantly dependent on nitridation temperature.