The self-assembled organic-inorganic hybrid materials such as bis(1,2,3,4-tetrahydroquinolinium) hexachlorostannate(IV) (1) and bis(1,2,3,4-tetrahydroquinolinium) hexabromostannate(IV) (2) have been synthesized for their huge applications in opto-non-linear devices. The hybrid materials (1) and (2) have been synthesized and their single crystals were grown by slow evaporation of solution technique (SEST) at room temperature. The presence of protonated NH2 group at 3396 cm–1 in both compounds are confirmed by FT-IR spectral analysis. Diffuse reflectance spectral measurements imply that the tunability of band gap is easily achieved by altering the halide ion. TG-DTA analysis reveals the thermal stability of the compounds is up to 205 °C. Bond valence sum (BVS) calculations performed on SnCl62− and SnBr62− anions (1) and (2), prove the formal oxidation state of tin in the compounds as 4+. The closed and open aperture Z-scan studies ascertained the nature of third order nonlinear optical refraction and absorption of the hybrids. The third-order nonlinear optical susceptibilities χ(3) for the two compounds (1) and (2) are found to be 1.57 × 10−7 esu and 1.46 × 10−7 esu respectively. Investigation of the intermolecular interactions and crystal packing using Hirshfeld surface analysis, derived by single-crystal XRD data, reveals the closer contacts associated with strong interactions. © 2021 Elsevier B.V.