The uranyl cation, UO₂²⁺ is an attractive metal center for the construction of metal organic framework (MOF) and coordination polymer (CP) materials. This linear, triatomic species consists of a central U(VI) ion with two coordinated oxygen atoms at distances on the order of 1.8 Ǻ. These sites tend to be terminal and thus force coordination (and ultimately polymerization) to the equatorial plane of the ion. An affinity for both carboxylate and pyridyl functional groups allows for not only a range of linker molecules to be used in the construction of extended topologies, but also multiple, distinct linker species. Further, complex speciation/hydrolysis of the uranyl cation under hydrothermal synthesis conditions results in a variety of secondary building units not seen in other MOF or CP systems. The synthesis, structures, roles of secondary linker species and luminescent behavior of several novel uranyl-carboxylate/pyridyl compounds will be presented, as will a series of heterometallic compounds wherein secondary metal centers influence topology and properties.