Addition of in situ reduced amidinato-methylaluminium chloride to acetylenes was observed. Whether the structure of the products contains an ethylene bridge or terminally bonded ethynyl groups was not determined. The reaction was carried out in the presence of a base, which facilitated the formation of the amidinato-methylaluminium chloride. The products were isolated and characterized by NMR spectroscopy. The reaction was found to be highly regioselective, with the amidinato-methylaluminium chloride adding to the acetylene in a 1,2-fashion. The reaction was also found to be highly stereoselective, with the amidinato-methylaluminium chloride adding to the acetylene in a cis-fashion. The reaction was found to be highly efficient, with the amidinato-methylaluminium chloride adding to the acetylene in a single step. The reaction was also found to be highly versatile, with the amidinato-methylaluminium chloride adding to a variety of acetylenes. The reaction was found to be highly useful, with the amidinato-methylaluminium chloride adding to acetylenes in a wide range of applications.