The separation of global and local motion for [Gd(DTPA−BA)−(CH2)n]x copolymers (see diagram) shows that, contrary to usual linear polymers, the global rotation can strongly contribute to proton relaxivity. The rate and mechanism of water exchange is not influenced by polymerization. The collective results for these three polymers have important implications for the design of polymeric species with very high proton relaxivities.