Gain‐guided, injection lasers using AlAsSb for optical confinement and a strained InAsSb/InAs multiquantum well active region were grown by metalorganic chemical vapor deposition. The semi‐metal properties of ap‐GaAsSb/n‐InAs heterojunction are utilized as a source for injection of electrons into the active region of the laser. In pulsed mode, the laser operated up to 210 K with an emission wavelength of 3.8–3.9 &mgr;m. We also report on the two‐color emission of a light‐emitting diode with two different active regions to demonstrate multistage operation of these ‘‘unipolar ’’ devices. ©1996 American Institute of Physics.