A new semiorganic nonlinear optical material, di-N-methylanilinium tetrachlorocadmiate(II) was grown by slow evaporation solution method at ambient temperature. The absorption of the compound was studied by UV–vis absorption spectral analysis. The suitability of the optical property was ascertained through optical transmittance study. The sharp and well defined Bragg peaks in the powder X-ray diffraction pattern confirm its crystallinity. Thermal stability and decomposition pattern of the compound were studied by using TG-DTG and DTA analyses. The different kinds of protons and carbons were assigned through nuclear magnetic resonance (NMR ( 13 C and 1 H)) spectroscopic techniques. The Fourier infrared spectrum (FTIR) characterizes the vibration frequencies due to NC, CCl, CdCl 4 2− and other chemical bond vibrations. The second harmonic generation (SHG) efficiency of the compound was measured by suing Kurtz–Perry powder techniques and it shows that the compound has SHG efficiency one and a half times greater than of potassium dihydrogen phosphate (KDP). The dielectric constant and dielectric loss of the compound decrease with increases in frequencies.