We have fabricated a p-n junction using a p-type conducting polyaniline layer deposited on an n-type porous silicon layer. This junction shows rectifying behaviour. The I-V curves can be fitted to a Schottky barrier model with a barrier height of 0.8 eV. The porous silicon shows an orange photoluminescence band due to recombination in the silicon quantum structures both before and after coating with polyaniline. The junction emits visible electroluminescence when a forward bias is applied. The emission band is very broad extending from 500 to 1 000 nm with a peak at 790 nm. Mechanisms for charge transfer between the porous silicon and polyaniline are discussed.