Theoretical investigation on planar N-6(4-) and N-4(2-) rings has been performed. The aromaticity of the rings has been analyzed through their nucleus independent chemical shift (NICS) values as well as the sigma-and pi-contribution of the Z-component of the induced magnetic field. Counter to a previously reported result [Chem. Phys. Lett. 432 (2006) 331], the N-6(4-) ring is found to be a local minimum and aromatic with planar D-6h symmetry. The N-4(2-) ring exhibits conflicting aromaticity like Al-4(4-). Both the N-6(4-) and N-4(2-) rings can be stabilized in presence of suitable counter cations and systems like N6Ca2 and N4Li2 can trap molecular hydrogen. (C) 2011 Elsevier B. V. All rights reserved.