An electronic device comprising a layer of a polymer having an electrically conductive or semiconductive main chain, wherein the chains of the polymer have an electrically conductive or semiconductive charge transporting end-group at each end thereof, and the polymer in the layer is organised in a lamellar structure having ordered regions, in which the polymer main chains are aligned with respect to each other, and boundary regions which separate the ordered regions and in which the degree of alignment between adjacent polymer main chains is less than that in the ordered regions.