We have been synthesizing Ln-carboxylate based metal organic framework (MOF) materials that utilize uncoordinated guest molecules (or ‘templates') to direct the formation of three-dimensional topologies. In addition to the structural influence of these species, bipyridines in particular also introduce a conjugated pi system that in turn serves as a chromophore for UV radiation. These guest molecules are capable of sensitizing fluorescence of the Ln metal centers within the MOF to produce highly luminescent materials. Synthesis, structural characterization and luminescent properties of several end member (Eu³⁺, Tb³⁺) MOFs, as well as the co-luminescence behavior of mixed Eu/Tb systems will be presented. The latter system shows a dual sensitization of the Eu³⁺ centers from both the guest bipyridine molecules, as well as from the Tb³⁺ centers.