Atomically-precise nanoclusters promise many of the desirable features of both nanoparticles and molecules. They typically have large absorption coefficients from the near infrared to the ultraviolet, 1 a large but finite electronic density of states, 2 small redox potentials, and tunability through changes in size, structure, doping, and ligands. At the same time, it is sometimes possible to purify them with exact compositional specificity, and thus exact synthetic control of their properties and behaviors is concievable using traditional chemical approaches. Their amenability to purification also allows their structures to be determined exactly using crystallography, revealing nanoscale structure-function relationships. This has led to a wide range of studies proposing nanoclusters as "designer" nanoparticles in contexts varying from biological sensing to catalysis.