Red and near-infrared (NIR)-emitting materials have collected rapidly growing attention because of their emerging applications in night-vision, information-secured displays, bio-imaging and diagnosis, etcs. However, in the case of conventional red emitting materials, quantum efficiency decreases as the wavelength become longer due to the lower energy gap, and their LEC devices exhibit relatively lower brightness as compared with materials emitting at shorter wavelengths. In this presentation, we report synthesis of red-emitting Ir complex (IR-red) with 40% improvement in quantum efficiency using quinoline (TQ) as a ligand. As synthesized IR-red was examined as a red light emitting dopant and used as guest molecules into a highly emissive but yellow light emitting Ir complex (IR-yellow). A host-guest system with IR-red and IR-yellow increased the emission output in red region and afforded a red-emitting LEC device with brightness of 300cd / m^2 or more. Further optimization of doping solution and a mechanism for drastic increase in LEC emission in red region will be discussed.