In this paper, a Br-containing diamine ligand of 2-(4-bromophenyl)-5-(pyridin-2-yl)-1,3,4-oxadiazole (referred to as BrPO) and its corresponding Re(I) complex of Re(CO) 3 (BrPO)Br are synthesized and studied in detail, including molecular structure, photophysical feature, thermal stability and electrochemical property. Experimental data suggest that Re(CO) 3 (BrPO)Br takes a octahedral coordination environment, and the π–π attraction between BrPO ligands makes complex molecules take a highly-ordered arrangement. Re(CO) 3 (BrPO)Br is found to be a yellow emitter peaking at 565nm with emission yield of 0.11 and excited state lifetime of 4.21μs. The emission comes from triplet excited state of ML&LLCT, where ML&LLCT means metal-to-ligand-charge-transfer and ligand-to-ligand-charge-transfer as suggested by theoretical calculation. The fluorescent component in the emissive center is minimized by the heavy-atom turbulence effect. Re(CO) 3 (BrPO)Br owns a high thermal decomposition of 280°C, with HOMO of −5.45eV and LUMO of −3.12eV. The optimal electroluminescent device using Re(CO) 3 (BrPO)Br as the emitting dopant gives a maximum brightness of 5906cd/m 2 and a maximum current efficiency of 5.6cd/A.