High-quality self-assembled heterostructures for polymer LEDs have been fabricated from PPV and newly synthesized copolymers of PPV and naphthalene. It is shown that the layer-by-layer self-assembly of multilayer structures has advantages with respect to control of the thickness and homogeneity of the polymer films compared to the conventional spin coating technique. The fabrication and characterization of the heterostructures are detailed and features of the electroluminescence and photoluminescence discussed.