A new semiorganic single crystal, catena-Poly[bis(4-methylbenzylammonium) [[dibromidocadmate(II)]-di-l-bromido]],[4MLBDCB], has been developed by evaporating the solvent at a 37 °C. It crystallizes in centrosymmetric space group Pnma. In the crystal structure, 4-methylbenzylammonium cation and tetrabromido cadmate anion are connected by N–H⋯Br and C-H⋯Br hydrogen bonds. Functional groups vibrations of 4MLBDCB were analysed by FT-Raman and FTIR spectroscopy. The stretching vibration of NH and CH shifted towards lower frequency side and their bending vibrations (–NH, –CH) to higher frequency when compared with pure 4 methylbenzylamine (4MLBA) vibrations. The observed variations in CH bond length are discussed. Presence of Raman active CdBr42− vibrations ensures the formation of the molecule. Transmittance bandwidth of the crystal extends from 260 and 1100 nm. In 1H and 13C NMR spectra, the observed variations in the chemical shifts are interpreted through intermolecular interactions. The presence of hydrogen bonds enhances the third order nonlinear susceptibility (χ3) value of the grown crystal and found to be 5.04 × 10−6 esu. The third order nonlinear optical parameters such as absorption coefficient (β) and refractive index (n2) are also determined using Z-scan technique.