Six macromolecular polyester ligands were synthesized by copolymerization of diethylenetrithenepentaacetic dianhydride with N -butyl

octyl

benzyl

p -toluenesulfonyl

phenyl and p-bromophenyl diethanolamine

respectively. Their Gd(Ⅲ)complexes were also prepared' The structures of these macromolecular polyester ligandsand their Gd(Ⅲ) complexes were characterized by 'H-NMR

IR

Elemental analysis and DSC. The molecular weight of these polyseter ligands were determined by VPO method. Average degree of polymerization of these copolymers were found to be around 4.Two of these macromolecular Gd(Ⅲ) complexes were chosen for the relaxation measurement.Preliminary results showed that the relaxivity (R1) of macromolecular GD(Ⅲ) Complex 3b and 3c han an enhancement of 40% and 36% in comparison with that of Gd-DTPA.