An unipolar organic injection laser in which electrically-stimulated intraband transitions result in lasing. An active region includes at least one organic injector layer and at least one organic emitter layer. Each organic emitter layer has a first energy level and a second energy level on a same side of an energy gap defined by a conduction band and a valance band. Charge carriers are injected through the organic injector layer into the first energy level of the organic emitter layer when a voltage is applied across active region. The difference in energy between the first and second energy levels produces radiative emissions when charge carriers transition from the first energy level to the second energy level. Population inversion is maintained between the first and second energy levels, producing stimulated emission and lasing.