Five mono-nuclear silver(I) complexes with the ligand 2,9dimethyl-1,10-phenanthroline, namely [Ag(DPEphos)(dmp)]BF 4 (1), (4), and [Ag(dppb)(dmp)]NO 3 ·CH 3 OH (5) {DPEphos = bis[2-(diphenylphosphanyl)phenyl]ether, dppb = 1,2bis(diphenylphosphanyl)benzene, dmp = 2,9-dimethyl-1,10-phenanthroline} were characterized by X-ray diffraction, IR, 1 H NMR, 31 P NMR and fluorescence spectroscopy. Their terahertz (THz) time-