Six azo disperse dyes were prepared by diazotizing 4-amino hippuric acid and coupled with barbituric acid and 2-thiobarbituric acid.Then, the products were reacted with aromatic aldehyde, sodium acetate, and acetic anhydride, and oxazolone derivatives were formed.Characterization of the dyes was here carried out by using UV-Vis, FT-IR, 1H NMR and 13C turbo air m3f24-1-n NMR, and mass spectroscopic techniques.The solvatochromic behavior of azo disperse dyes was evaluated in various solvents.The effects of substituents of aromatic aldehyde, barbiturate, and thiobarbiturate ring on the color of dyes were investigated.