We report an enhanced luminescence of cast films of poly(p-phenylenevinylene) (PPV), where the energy transfer among adjacent polymer chains was controlled by varying the concentration of counterions in the synthesis. Using as precursor poly(xylylidenetetrahydrothiophenium) with dodecylbenzenesulfonate as counter ions (PTHT-DBS) in 1:3 M basis led not only to the strongest but also the most polarized emission. Both the intensity and degree of polarization could be controlled, provided that the conversion temperature was considerably lower than the T-g of PPV. These results may be exploited in optimizing organic electronic devices, for which annealing is needed. (C) 2014 Elsevier B.V. All rights reserved.