We report the first observations of electroluminescence (EL) and lasing in laser structures with high Al-content (x=0.64, Eg=1.474 eV) cladding layers and a narrow-gap InGaAsSb active layer (Eg=0.326 eV at T=77K). The structures are LPE-grown lattice-matched to GaSb substrate. Band energy diagrams of the laser structures had strongly asymmetric band offsets. The heterojunction between high Al-content layer and InGaAsSb narrow-gap active layer has a type II broken-gap alignment at 300K. In this laser structure spontaneous emission was obtained at λ=3.8μm at T=77K and λ=4.25 μm at T=300K. Full width at half maximum (FWHM) of emission band was 34 meV. Emission intensity decreased by a factor of 30 from T=77K to 300K. Lasing with single dominant mode was achieved at λ=3.774 μm (T=80K) in pulsed mode. Threshold current as low as 60 mA and characteristic temperature T0=26K were obtained at T=80–120K.