Two azo compounds (L1 and L2) were synthesized from aromatic amine and amino benzoic acid by the diazo coupling reaction. The chemical structure of two azo compounds was characterized by IR and NMR. The the acid-alkaline based discoloration and optical properties of the compounds were also studied. The results show that the compounds L1 and L2 have high molar absorptivity and good acid-base discoloration, and can be used as a potential fluorescent probes.