The structures of pyrazine (pyz) and pyridazine (pydz) molecules and their silver(I) complexes with saccharinate (sac), [Ag-2(sac)(2)(-pydz)(2)] and [Ag(sac)(pyz)](n), have been optimized by density functional theory (DFT) to study their luminescence properties. The pyz, pydz and their silver(I) complexes luminesce in solution at room temperature. The luminescence behavior of the ligands and silver(I) complexes was mainly originated from ligand-centered transitions. A very good agreement was found between the HOMO-LUMO energy gap and the experimental emission energy for the silver(I) complexes, but in the case of pyz and pydz, the calculated energies were much higher. (c) 2006 Elsevier B.V. All rights reserved.