Single crystal of Ba2SbGaS5 has been synthesized by the high temperature solidstate reaction method. The compound crystallizes in the orthorhombic space group Pnma with a = 12.177(4), b = 8.880(3), c = 8.982(3), V = 971.4(6)3 , Z = 4, Dc = 4.284 g/cm3 , = 14.487 mm-1 , F(000) = 1096, the final R = 0.0171 and wR = 0.0384 for all data. The structure comprises an infinite one-dimensional 1∞SbGaS54- anionic chain constructed from the GaS4 tetrahedra and the SbS5 polyhedra via sharing edge alternately. The paralleled 1∞SbGaS54- anionic chains engage with each other and form the two-dimensional Sb-Ga-S layer perpendicular to a-axis with the isolated Ba2+ cations arranged between layers. The IR spectrum and the UV-Vis spectrum have been investigated. Also, the first-principles band structure and density of states calculations indicate that the compound belongs to indirect semiconductor with the band gap of 2.1 eV, which is supported by the UV-Vis diffuse reflectance results. Single crystal of Ba2SbGaS5 has been synthesized by the high temperature solid state reaction method. The compound crystallizes in the orthorhombic space group Pnma with a = 12.177 (4), b = 8.880 (3), c = 8.982 (6) 3, Z = 4, Dc = 4.284 g / cm3, = 14.487 mm -1, F (000) = 1096, the final R = 0.0171 and wR = 0.0384 for all data. dimensional 1 ∞ SbGaS 54-anionic chain constructed from the GaS 4 tetrahedra and the SbS 5 polyhedra via sharing edge alternating. The paralleled 1 ∞ SbGaS 54-anionic chains engage with each other and form the two-dimensional Sb-Ga-S layer perpendicular to a-axis The first spectrum of the spectrum and the UV-Vis spectrum have been investigated. Also, the first-principles band structure and density of the states of the coupled semiconductor with the band gap of 2.1 eV , which is supported by the UV-Vis diffuse reflectance results.