6-Methoxy naphthaldehyde is prepared by the Grignard reaction of 2-bromo 6-methoxy naphthalene with triethylorthoformate. The formation of the compound is confirmed by recording IR and <sup>1</sup>H NMR spectra. The SHG frequency conversion efficiency of this compound was measured by powder technique using Nd: YAG laser. This compound showed NLO property 0.59 times that of urea. The crystal system is found out by single crystal X-Ray diffraction studies and the crystal system found to be orthorhombic and space group P<sub>212121</sub> with cell parameters : a = 15.657(10) Å, b =16.385(4)Å, c = 7.491(15) Å, α = 90<sup>o</sup>, β = 90<sup>o</sup>, γ = 90<sup>o</sup>. Its bulk crystal of the size 39x 41x14mm<sup>3</sup> is grown from acetone solvent by slow evaporation technique.
Single crystals of nonlinear optical material 1-(4-methylphenyl)-3-(4-methoxyphenyl)-2-propen-1-one were successfully grown for the first time by slow evaporation method up to a dimension 25 x 15 x 2 mm<sup>3</sup>. Optical studies such as UV-Visible, energy band gap, refractive index, second harmonic efficiency have been performed. The UV-Visible spectrum reveals that the crystal is transparent in the entire visible region and absorption takes place in the UV-region. Using UV-Vis data, the energy band gap was found and it shows an energy band gap of 2.7eV for this material. The refractive index was measured using Brewster's angle method. The Kurtz powder second harmonic generation test shows that the compound is a potential candidate for photonic applications. From the I-V measurements the dc conductivity of these crystals has been studied and it is found to be very low. Dielectric constant, dielectric loss and ac conductivity of a grown single crystal have been studied in the frequency range 120Hz to 100 kHz at the room temperature and proper interpretations were drawn. The micro hardness test was carried out and the load dependence hardness was studied.