We present photoluminescence (PL), UV absorption, electroluminescence and x‐ray reflectivity studies of self‐assembled multilayer films containing alternate layers of conjugated copolymers, and nonconjugated insulating polymers. We show that the PL emission properties of these organic quantum wells can be ‘‘tuned’’ by a proper choice of the conjugated copolymer and the thickness of the insulating layers. Particularly, some of the self‐assembled ultrathin films containing thin (∼7 A˚) insulating polymeric layers exhibit a blue shift upon decreasing the thickness of the assembly. The PL shift is roughly proportional to 1/d2wheredis the thickness of the assembly, as expected for confined photogenerated electron‐hole pair in an infinite square potential well. In contrast, the PL emission of similar assemblies but containing thick (∼40 A˚) insulating layers is independent of the assembly thickness and exhibit emission in the blue. This may suggest a strong spatial confinement. Light emitting diodes based on self‐assembled multilayer films with improved efficiency and stability and with threshold voltage as low as 2.6 V could be fabricated. ©1996 American Institute of Physics.