Schiff bases and their metal complexes are very important as catalysts in various biological, medicinal and pharmaceutical fields [1]. This work presents the interaction of Fe(III) cation with the Schiff bases derived from o-vanillin and 1,2-diaminobenzene (6-(((2-aminophenyl)imino)methyl)-2- methoxyphenol =L). This ligand is poorly soluble (105 M) in aqueous solution and complexation studies are difficult for the low concentration of species that are formed. Favorable conditions for equilibrium analysis are obtained by increasing the concentration of the metal compared to that of the ligand. The experimental data were carried out in the form of spectrophotometric and potentiometric titration by varying the hydrogenionic concentration in the range 1  pH  6. The measurements were carried out at 25 C in 0.1 M NaCl as ionic medium. The variation of the spectrofluorimetric spectra as a function of concentration of the metal is shown in Figure. The change in fluorescence intensity a function of the metal / ligand molar ratio, at constant pH, shows the formation of a complex with 2:1 stoichiometry ratio. Similar results are obtained from UV-VIS spectrophotometric measurements; a speciation model is obtained by processing the experimental data using Hyperquad program.