A NEW azo compound 2 (2`-hydroxy naphthyl azo-) benzo-
thiazole (HNABT) has been synthesized. Bands of the ligand and the formed complexes of Co(II), Cu(II) and Fe(III) are assigned using FT-IR spectra. The electronic absorption spectra of the ligand in pure organic solvents of different polarity and also in buffer solution of varying pH are investigated. Acid ionization constant and stability formation constant of complexes were determined. A sensitive spectrophotometric method for the micro determination of metals using the azo compound, as a new chromogenic ligand is established. This method is successfully used for the determination of Co(II), Cu(II) and Fe(III) in the presence of foreign ions and in solutions .