Ligand compositions for use in preparing discrete coated nanostructures are provided, as well as the coated nanostructures themselves and devices incorporating same. Methods for post-deposition shell formation on a nanostructure, for reversibly modifying nanostructures, and for manipulating the electronic properties of nanostructures are also provided. The ligands and coated nanostructures of the present invention are particularly useful for close packed nanostructure compositions, which can have improved quantum confinement and/or reduced cross-talk between nanostructures. Ligands of the present invention are also useful for manipulating the electronic properties of nanostructure compositions (e. g. , by modulating energy levels, creating internal bias fields, reducing charge transfer or leakage, etc. ).