An organic electroluminescent device and a method of manufacturing such a device. By patterned exposure of an alkylatable-compound-containing organic layer of the device to an alkylating agent, a device is obtained which, in operation, exhibits patterned light emission, without it being necessary to structure the electrode layers. A salt is locally formed by means of alkylating in accordance with a pattern. If the salt contains ions which can move under the influence of an electric field, the threshold voltage necessary to produce light emission is reduced.