Seven acentric sulfides Ba(CuZ)SnS (Z = Mg, Mn, Zn, Cd, In, Bi, Sn) were grown by a high-temperature salt flux method. The crystal structures of the Ba(CuZ)SnS (Z = Mg, Mn, Zn, Cd, In, Bi, Sn) compounds were determined by single crystal X-ray diffraction with the aid of solid-state NMR spectroscopy. The Ba(CuZ)SnS (Z = Mg, Mn, Zn, Cd, In, Bi) compounds are isostructural and crystallize in the BaAgSnS structure type. The Sn-containing compound exhibits high structural similarity to Ba(CuZ)SnS (Z = Mg, Mn, Zn, Cd, In, Bi) with the presence of an interstitial atomic position partially occupied by Sn atoms. The chemical bonding characteristics of Ba(CuSn)SnS were understood with electron localization function calculations coupled with crystal orbital Hamilton population calculations. The Ba−S and Cu−S interactions are dominantly ionic, but the Sn−S interactions consist of strong covalent bonding characteristics in Ba(CuSn)SnS. The monovalent Cu atoms, mixed with certain metals with various oxidation states, significantly shift the optical properties of the Ba(CuZ)SnS (Z = Mg, Mn, Zn, Cd, In, Bi) compounds. This results in a good balance between the second harmonic generation (SHG) response and laser damage threshold (LDT). Ba(CuZn)SnS possesses a high SHG response and a high LDT of 2.8 × AGS and 3 × AGS, respectively. A density functional theory calculation revealed that CuS and SnS tetrahedra significantly contribute to the SHG response in Ba(CuMg)SnS, which also confirmed that CuS tetrahedra are crucial for the stability and optical properties of the Ba(CuZ)SnS (Z = Mg, Mn, Zn, Cd, In, Bi, Sn) compounds revealed by electronic structure analysis.