The formation of structurally complex metal-organic polygons, polyhedra, and prisms (MOPs) is greatly facilitated by self-assembly methods which furnish them in single, one-pot reactions. An ever-growing library of organic ligands (donors) and metal/organometallic complexes with substitutionally labile coordination sites (acceptors) serves as the basis for a suite of metallacycles and cages characterized by their well-defined internal cavities and predictable topologies. As the structural chemistry of these materials matures from studies emphasizing synthetic routes, a priority on functional assemblies has emerged and will be highlighted. Towards this end, the rigid organic backbones that once served solely as structural elements have more recently been exploited for their ability to impart interesting photophysical properties to their parent MOPs. Strategies include tethering pendant fluorophores through covalent coupling chemistry and selecting inherently emissive building blocks. These approaches are mirrored in efforts to obtain electrochemically active materials: redox-active moieties may be coupled to the periphery of a given MOP. Alternatively, the metal nodes may prove competent for reversible redox chemistry, motivating applications in catalysis and charge carrying devices.