A series of pi-conjugated co-polymers {(P)[Re](x) (x = 0. 1, 0.2, and 0.5)1 incorporated with fac-(bpy)Re(I)-(CO)(3)CI (bpy = 2,2'-bipyridine, Re = rhenium) chromophores in the backbones have been synthesized. The Re(I) chromophore contents were accurately controlled by the contents of bpy segments in (P)[bpy](x) (x = 0.1, 0.2, and 0.5) co-polymers. The structures of (P)[Re](x) co-polymers were characterized by H-1 nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR) analysis, and their optical and electronic properties were measured by electronic absorption, steady-state and time-resolved fluorescence, and field-induced surface photovoltaic spectroscopy (SPS). At room temperature, the characteristic metal-to-ligand charge-transfer (IMLCT) absorption band and red emission of IMLCT from fac-(bpy)Re(l)(CO)3Cl chromophores can be observed. Electroluminescence (EL) devices that use (P)[Re]x co-polymers as the active layers showed enhanced red IMLCT emission. However, the photoluminescence (PL) and EL efficiency of (P)[Re](x) co-polymers were lower, compared to those of a fac-(bpy)Re(I)(CO)(3)Cl molecularly doped polymers. The lower emission of (P)[Re](x) co-polymers is conceivably related to the charge carrier separation of localized electron-hole pairs (excitions) in the sites of fac-(bpy)Re(CO)(3)Cl as they became incorporated with extensive pi-conjugation chains. Further studies of density functional theory (DFT) calculation and SPS provided proof of charge carrier separation in (P)[Re]x co-polymers. The efficient charge carrier separation would decrease the efficiency of PL and EL but enhance the photovoltaic efficiency, which meant a more suitable application of the types of pi-conjugated polymers incorporated with transition-metal complexes in their backbones.