Multilayer heterostructure thin films of electroactive polymers such as poly (p-phenylene vinylene), PPV, precursor and sulfonated polyaniline, SPAn, have been successfully fabricated via process based on the spontaneous self-assembly of conjugated polyion on a substrate. We have prepared SPAnIPPV multilayer heterostructures light-emitting diodes (LEDs) using this electrostatic self-assembly technique and discussed the electroluminescent (EL) properties. The SPAnIPPV monolayer LED emits greenish-yellow light, but SPAnIPPV multilayer LED emits bluish-green light and there is a slight shift between the two spectra of these devices. These results can be interpreted in terms of the confinement effect of carriers in the superlattice structure consisting of SPAnIPPV multilayer system.