Theoretical studies of germanazene rings [(Ge II –NR) 2,3 ; R=H, Me, CN, Ph] have been performed at the DFT/B3LYP level. The fully optimized geometrical structures display four or six-membered planar rings of alternating germanium and nitrogen, in good agreement with the available X-ray experimental data. The hypothetical molecule (GeN–H) 2 presents only a small distortion from planarity. Although the planar conformation could indicate some degree of delocalization, the stabilization energy – estimated using the concept of homodesmotic reactions – indicates very little or no aromatic character in these molecules. The easy experimental formation of these germanazenes can be explained by di- (or tri-)merisation of the transient monomeric germylene-imine GeNR in its triplet state. When R=CN, in conformity with the experimental results, the most stable species is the isomeric carbodiimide form (GeNCN) n , a result which is easily explained by the maximum spin density on the terminal nitrogen in the calculated monomer.