Three organically templated uranium(VI) carboxyphosphonates, [C10H10N2][(UO2)(3)(PPA)(2)(HPPA)(H2O)]center dot 3H(2)O (1), [C12H12N2][(UO2)(3)(PPA)(2)(HPPA)(H2O)]center dot 2H(2)O (2), and [C12H14N2][(UO2)(3)(PPA)(2)(HPPA)(H2O)]center dot 2H(2)O (3) have been prepared from hydrothermal reactions of UO2(NO3)(2)center dot 6H(2)O and phosphonoacetic acid (H2O3PCH2CO2H, H(3)PPA) in the presence of 4,4'-dipyridyl, 1,2-bis(4-pyridyl)-ethylene and 1 2-bis(4-pyridyl)-ethane. The crystal structures of 1-3 are built from UO7 units linked via phosphonoacetate molecules to form 2-dimensional [(UO2)(3)(PPA)(2)(HPPA)(H2O)](2-) networks which are charge balanced by doubly protonated bipyridyl molecules. Interaction of the pyridyl molecules with other functionalities present in 1-3 result in relatively strong N-H center dot center dot center dot O (2.707-3.155 angstrom) and weaker C-H center dot center dot center dot O (2.948-3.237 angstrom) interactions that constitute the interlayer. Water-carboxylate O-H center dot center dot center dot O hydrogen bonding (2.548-2.675 angstrom) in 1-3 and pi-pi interactions (3.708 angstrom) between pyridyl rings in 2 also exist in these materials. Reported herein are the syntheses, structural characterization, and thermal and fluorescent behavior of 1-3.