Chelating properties towards the metallic cation Cu2+ of polycondensates bearing aminoacetic acid groups along the polymer chain, synthesized from diethylenetriaminepentaacetic acid bisanhydride with diols and diamines, have been investigated. All the complexes are water soluble. Potentiometric titrations and visible and ultraviolet spectrophotometry show the formation of different complexes according to pH and dissociation constants point out the influence of the density of COOH groups along the polymer chain according to the diol or diamine comonomer. The behaviour of the synthesized polycondensates towards gadolinium has also been studied in order to evaluate their potential use as contrast agents for Magnetic Resonance Imaging by measure of the relaxivities of the obtained complexes.