An LED, and in particular an LED employing emissive semi-conductors such as conjugated polymeric materials, consists of a pair of electrodes, one or more intermediate semi-conductor layers arranged therebetween and optionally one or more futher layers, and incorporates a microstructured feature adapted to manipulate spontaneous emission or propagation of light. The invention also consists of a method for the production of such an LED and the use of such a LED as an light emitting display.