A family of uranyl diphosphonates have been hydrothermally synthesized using various flexible diphosphonic acids and Zn(UO2)(OAc)4路7H2O in the presence of bipy or phen. Single-crystal X-ray analyses indicate that these compounds represent the first examples of uranyl phosphonates with heterometallic UVI鈺怬鈥擹nII cation鈥揷ation interactions.