In this thesis, two new polymeric Schiff base ligands L2 and L4, were synthesized using 2-hydroxybenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde, 5-aminoisophthalic acid and triphenyl phosphite (TPP), in tetrabutylammonium bromide (TBAB) ionic liquid as solvent. The nanostructured complexes M-L2 and M-L4 were then synthesized using Ni2+, Cu2+, and Mn3+. The synthesized ligands and complexes, were characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and field-emission scanning electron microscopy (FE-SEM). The thermal stability of the complexes was confirmed using TGA. FE-SEM analysis indicated porous buildings of the synthesized polymers. In the first section of the thesis, the polyamide ligand L2 and its complex Cu-L2, were comparatively applied for the removal of Pb(II) ions from aqueous solutions. The adsorption was significantly dependent on the contact time, temperature, initial concentration of metal ions, and pH. The best adsorption occurred at pH 6. The rate of Pb(II) adsorption on the adsorbents followed the pseudo-second-order model. At temperature range of 30–60 °C, the adsorption reaction of Pb(II) ions through ligand and its complex were endothermic. The equilibrium isotherm data for Pb(II) ions adsorption, were fitted to the Langmuir model for PA ligand and its complex. Furthermore, the maximum adsorption capacity (qm) of the ligand L2 was more than that of the complex Cu-L2 due to more active sites of the former. In the second section of the thesis, the polyamide complex Mn-L2, was applied to eliminate Hg(II) and Cd ions from aquatic solutions. The sample achieved equilibrium in 30 min at the pH of 7. The adsorption data of Hg(II) and Cd ions, were fitted to the Langmuir and Freundlich models, respectively. At temperature range of 30–60 °C, the adsorption reaction of Hg(II) and Cd ions through complex was exothermic. A pseudo-second-order rate pattern was adapted to the kinetic data of Hg(II) and Cd ions. The maximum adsorption capacities of Hg(II) and Cd ions, were found to be 12.38 mg g?1 and 16.45 mg g?1, respectively. It was also easy to recover and reuse. In the last part, the six complexes were used as catalysts in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in an aqueous phase in the presence of sodium borohydride (NaBH4). In this work, the catalytic reactivity of nanostructured complexes, was compared using the rate constant (k) of the reaction. The reaction time for the reduction of 4-NP, was 5–14 min for different complexes. The catalytic activity of complex Ni-L2 was more than the other complexes and had a recovery capability for 7 cycles.