Mechanochemistry provides a rapid, efficient route to half‐sandwich iridium and rhodium complexes from [MCp*(μ‐Cl)Cl]2 (M = Ir, Rh) and 8‐hydroxyquinoline‐2‐carbaldehyde without the need for Schlenk manipulation, inert gas protection, or dry solvents. Furthermore, post‐synthetic modification of the half‐sandwich metal complexes has been carried out via a mechanochemical Wittig reaction between half‐sandwich metal complex and phosphorus ylide. All complexes were fully characterized by 1H and 13C NMR spectra, infrared spectroscopy, mass spectrometry, and single‐crystal X‐ray diffraction method. The half‐sandwich rhodium complexes exhibited high catalytic activity towards the amide synthesis between aldehyde and hydroxylamine hydrochloride (NH2OH·HCl) with a broad functional group tolerance.