A series of novel aromatic compounds ScN6-, VN6+, Ca2N6, and ScN6CU, including a previously reported TiN6, are found to be local minima with C-6v, C-6v, D-6h, and C-s symmetry, respectively, at the B3LY-P/6-311+G* level of theory. These compounds may be regarded as 10 pi-electron complexes containing one or two metal cations and a planar N-6(4-) ring. They are predicted to have aromatic character. The nucleus-independent chemical shifts (NICS), the molecular orbitals, and the HOMO-LUMO gap analysis confirm that the planar N-6(4-) ring indeed exhibits aromaticity, which is remarkably enhanced by the incorporation of metal atom in these metal-N-6 molecules. (c) 2006 Elsevier B.V. All rights reserved.