In this research, the phase behavior and optical-electro properties of a liquid crystalline composite composed of a nematic liquid crystal with a strong polar end group and a discotic liquid crystal with weak side chains was studied A special electric-optic effect was observed at this binary system with a weight ratio range from 80/20~90/10 in the nematic phase owing to its high viscosity. The bistable opaque-transparent states change was investigated when applying AC electric fields on the binary composites under different temperatures.