GaSb based III-V heterostuctures are attractive for optoelectronic devices such as midin- frared lasers, detectors, and thermophotovoltaics (TPVs). In this paper the growth and characterization of GaInAsSb and GaAlAsSb quaternary layers, lat-tice-matched to GaSb substrate, are reported, with a particular focus on these alloys for TPV devi-ces. High-quality with a mirror-like surface morphology epilayers Ga1-x InxAsy Sb1-y with In content x in the range 0.1-0.22 and Ga1-xAlxAsySb1-y layers with Al content up to 0.3 in the solid are grown by Liquid-Phase Epitaxy (LPE) from In- and Ga-rich melt, respectively. The compositions of the quaternary compounds are determined by X-ray microanalysis. The crystalline quality of GaInAsSb/ GaSb and GaAlAsSb/GaSb heterostuctures is studied by X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements.