The present paper reports the synthesis and XRD characterization of 1- (2, 5- diméthoxyphénylazo)-2-naphtol which are prepared by diazotization and copulation reaction using 2, 5- diméthoxyaniline and β-naphtol as a coupling component. After recrystallization in pentane,the azo-compound was isolated as brown reddish crystal plates. XRD data analysis shows that our compound of empirical formula C18H16N2O3 crystallizes in space group Pbca orthorhombic system with: a = 12.09390 Å; b = 15.61670 Å; c = 16.50370 Å; α =90.00°; β = 90.00°;γ =90.00°; Z = 8.