The present invention provides metal-containing compounds that include at least one .beta.-diketiminate ligand, and methods of making and using the same. In some embodiments, the metal-containing compounds are homoleptic complexes that include unsymmetrical .beta.-diketiminate ligands. In other embodiments, the metal-containing compounds are heteroleptic complexes including at least one .beta.-diketiminate ligand. The compounds can be used to deposit metal-containing layers using vapor deposition methods. Vapor deposition systems including the compounds are also provided. Sources for .beta.-diketiminate ligands are also provided.