The mono-and dinuclear Cu(I) complexes [CuI(PPh 3 )(pmtz)] (1) and [{Cu(PPh 3 ) 2 } 2 (l-pmtz)](ClO 4 ) 2 (2), where pmtz is 3-(2-pyrimidinyl)-1,2,4-triazine, have been synthesized and characterized. Single-crystal X-ray diffraction analysis reveals that the pmtz acts as a bidentate ligand in complex 1, whereas in complex 2 the pmtz coordinates as a bis-bidentate chelate, assembling two identical {Cu(PPh 3 ) 2 } moieties into a copper(I) dimer with a triple-decker sandwich structure involving phenyl/pmtz/ phenyl p-p interactions. The UV-vis spectra of complexes 1 and 2 show low-energy absorptions at 350-550 nm, assigned to the Cu(I) to pmtz MLCT transition, probably mixed with some XLCT character for 1. The absorption of 2 is blue-shifted relative to that of 1 due to the substitution of the iodide of 1 with the p-acceptor ligand PPh 3 . Complexes 1 and 2 are non-emissive, both in solution and in the solid state, most likely owing to the electronic effects induced by the additional nitrogen donor of pmtz compared to 2,2 0 -bipyrimidine.