Abstract: Metal-organic frameworks (MOFs) are crystalline porous materials that include metal ions linked together into periodic structures via organic ligands. MOFs that contain lanthanide ions are a new class of visible and near-IR luminescent materials, suitable for a broad range of applications. For example, the MOF framework afforded by 2,5-dimethoxy-1,4-phenylene)di-2,1-ethenediyl]bis-carboxylate is associated with unusually long luminescence lifetimes. Thus, a complex of this ligand with a lanthanide provides a sharp emission profile, coupled with a comparatively long signal lifetime, for an unusually high luminescence. More generally, lanthanide-MOF systems exhibit several advantages that are ideal for barcoded materials, due to the photophysical attributes of lanthanide cations and the well-defined organization of the MOF structure.