A novel plasma-polymerized 3-quinolinecarbonitrile (PP3QCN) thin film was prepared by plasma polymerization of 3-quinolinecarbonitrile (3QCN) for the first time. The PP3QCN thin films show a blue emission with a narrow peak at similar to 475 nm and there appeared a relatively high intensity of PL peak. The EL devices with PP3QCN as electroluminescent layer sandwiched between ITO and Al were fabricated. It was found that the ITO/PP3QCN/Al devices also show a blue emission and PP3QCN thin film was stable and appropriate for the electroluminescent layer. The external quantum efficiency of ITO/PP3QCN/Al devices can reach to 0.0068%. The plasma-polymerized conjugated polynitrile thin film obtained from 3QCN precursor might be a promising material for application in LED and photodiode device. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 1858-1862, 2009