The organic material 3,4,5-trimethoxybenzaldehyde has been grown by slow evaporation technique using methanol as solvent. Single crystal X-ray diffraction studies shows that the grown 3,4,5-trimethoxybenzaldehyde single crystal belongs to the monoclinic system with the centrosymmetric space group P2 1 /c. FTIR and FT-Raman spectra were recorded to identify the functional groups present in the crystal. The optical property of the grown crystal was analyzed by UV-Vis-NIR measurement. The thermal property of the grown crystal was analysed by thermogravimetric (TG) and differential thermal analyses (DTA). The dielectric studies were analyzed by using the parallel plate capacitor method. The third order nonlinear optical properties of 3,4,5-trimethoxybenzaldehyde was measured by the Z-scan technique using 532 nm diode pumped continuous wave (CW) Nd:YAG laser. The mechanical property of the grown crystal was analysed by using microhardness studies. © 2019 Elsevier Ltd