A white light emitting device having an anode and a cathode and therebetween an organic electroluminescent layer which emits white light on the provision of a current between the anode and the cathode, said organic electroluminescent layer including a plurality of electroluminescent zones in laterally separated arrangement, the first of said electroluminescent zones including a first polymer and the second of said electroluminescent zones including a second polymer, wherein the first polymer includes a fluorescent blue light emitting species and the second polymer includes a fluorescent green light emitting species, said first and/or second zones further including a phosphorescent red light emitting species, such that together with the blue emitting species results in the emission of white light, said first and second polymers being physically incompatible so that separation of the zones pertains.