A molecular design approach is used to develop thermally responsive metal affinity hydrogels of N-isopropylacrylamide which can retain the nature of the overall volumetric response of the base gels and provide highly specific affinity separation. The synthesis of a novel iminodiacetic acid monomer to obtain metal affinity hydrogels with the right hydrophobic/hydrophilic balance is described and compared to a grafting technique presented in an earlier study. Copolymerization of this monomer with N-isopropylacrylamide and detailed characterization of both materials by various spectroscopic and elemental analysis techniques are presented. Preliminary experiments on the equilibrium swelling and critical analysis of the phase transition of the N-isopropylacrylamide gels incorporated with these novel metal affinity groups indicate that these gels retain the phase transition behavior of the base gels.