Communication: Polarized photoluminescence (PL) from conjugated polymers has, in the past, attracted less attention than polarized electroluminescence (EL), despite possible applications in liquid crystal displays. A systematic investigation is presented of the structure-property relationships in oriented films of blends of different poly(2,5-dialkoxy-p-phenyleneethynylene)s with ultrahigh molecular weight polyethylene, which exhibit highly polarized PL following gel processing and tensile deformation. Based on the experimental results, a new model is suggested for what occurs during orientation of the blends.