Five　mono-nuclear　silver(I)　complexes　with　the　ligand　2,9-dimethyl-1,10-phenanthroline,　namely　[Ag(DPEphos)(dmp)]BF4　(1),　[Ag(DPEphos)(dmp)]CF3SO3　(2),　[Ag(DPEphos)(dmp)]ClO4　(3),　[Ag(DPEphos)(dmp)]NO3　(4),　and　[Ag(dppb)(dmp)]NO3　center　dot　CH3OH　(5)　{DPEphos　=　bis[2-(diphenylphosphanyl)phenyl]ether,　dppb　=　1,2-bis(diphenylphosphanyl)benzene,　dmp　=　2,9-dimethyl-1,10-phenanthroline}　were　characterized　by　X-ray　diffraction,　IR,　H-1　NMR,　P-31　NMR　and　fluorescence　spectroscopy.　Their　terahertz　(THz)　time-domain　spectra　were　also　studied.　In　these　complexes　the　silver(I),　which　is　coordinated　by　two　kinds　of　chelating　ligands,　adopts　four-coordinate　modes　to　generate　mono-nuclear　structures.　In　complexes　1,　3-5,　offset　pi　center　dot　center　dot　center　dot　pi　weak　interactions　exist　between　the　neighboring　benzene　rings.　In　the　P-31　NMR　spectra,　there　exist　splitting　signals　(dd),　which　can　be　attributed　to　the　coupling　of　the　Ag-107,Ag-109-P-31.　All　the　emission　peaks　of　these　complexes　are　attributed　to　ligand-centered　excited　states.