A new ligand N,N-bis［(diphenylphosphino)methyl］-2-pyridinylamine (L) and its luminescent dinuclear copper(Ⅰ) complex ［CuBrL］2 (1) were synthesized and characterized by mass spectrometry, elemental analysis, NMR and electronic spectroscopies. The structure of complex 1 was determined by X-ray crystal analysis to be a dinuclear complex with a pseudo-tetrahedral geometry. The complex 1 crystallizes in a triclinic space group P-1 and has two copper(Ⅰ) centers bridged by two halogen ligands to form the dinuclear structure with a four-membered Cu2Br2 ring. The Cu-Cu distance in complex 1 is 0.306 0 nm which is longer than a sum of Van der Waals radius of two copper(Ⅰ) atoms. Therefore there is no substantial interaction between the two copper(Ⅰ) centers in complex 1. DFT calculations indicate that the electron density of HOMO is distributed mainly over the copper, bromine and phosphorus atoms, while that of LUMO is localized on the ligand. Our work shows that there are two mechanisms to form the the lowest excited state of complex 1, i.e. the metal-to-ligand charge transfer (MLCT) and halogen-to-ligand charge transfer (XLCT).