Two new chromogenic receptors 1,2-[1-(3-imino-4-hydroxophenylazobenzene)]-4-chlorobenzene (1 a) and 1,2-[1-(3-imino-4hydroxophenylazo-4-nitrobenzene)]-4-chlorobenzene (1 b) have been designed and chearcterized for detection of some transition metal ions in DMSO solution by UV/Vis spectroscopy. Upon addition of Cd 2 + , Zn 2 + and Cu 2 + ions to 1 a in DMSO, the peak at 460 nm increases in intensity, while the band at 352 nm decreases in intensity and approximately disappears. n!p* transition of azo groups of 1 a decreases in intensity after adding Hg 2 + ions and does not change after adding Ni 2 + ions. This indicates high tendency of 1 a towards Cd 2 + , Zn 2 + and Cu 2 + against Ni 2 + and Hg 2 + ions. Compound 1 b shows some color changes after addition of metal ions. Upon addition of all metal ions to 1 b in DMSO, the band at 560 nm increases in intensity with the hypsochromic shift for Cu 2 + , Zn 2 + , Co 2 + and Ni 2 + . But the largest blue shift (-67 nm) is seen after adding Cu 2 + ion with remarkable color change from violet-green to orange. Benesi-Hildebrand plot and Job's method are used for determination of binding constant (K a ) and stoichiometry of formed complexes with 1 b. Then, complex Cu(II) with 1 b is synthezied for recognition of binding sites of ligand. The results indicate that 1 b behaves as one tetradentate ligand with N and O donor atoms when bound to Cu(II). Moreover, the study of antioxidant properties of 1 a and 1 b with DPPH method reveals good and significant activity.[a] Dr.