Abstract: Extending precision synthesis from the molecular scale to the nanoscale is crucial for the atomic-level engineering of nanocrystals for their applications in energy, information, and biomedical nanotechnologies. However, precision nanosynthesis has been a significant challenge due to the complexity of nanostructures. A nanocrystal contains ~10s to ~10,000s of atoms in the core, metal-ligand coordination complexes at the interfaces, and organic molecules on the surfaces.