Layers of solid solutions (InSb)1-x(Sn2)x on (100) GaAs and (100) GaP substrates were grown by liquid phase epitaxy from an indium melt solution. The solid solution (InSb)1-x(Sn2)x (0 х 0.05) had a mono-crystal structure with the orientation (100), constant of the lattice as.s. = 6.486 Å and the hole conductivity type. The spectral dependence of the absorption coefficient was used to estimate the band gap of the epitaxial layer of the solid solution, which was 0.11 eV. The spectral photosensitivity of n-GaAs–p-(InSb)1-x(Sn2)x and n-GaP–p-(InSb)1-x(Sn2)x heterostructures covers the wavelength range from 1.0 to 5.3 μm.