The syntheses of ditbutylaluminium and -gallium iodide via metathesis reactions of the respective chlorides with lithium iodide are reported. The compounds were identified by elemental analyses, multinuclear NMR spectroscopy (1H, 13C, 27Al) and mass spectra (EI). The structures obtained by single crystal X-ray diffraction reveal that the new compound Bu2AlI crystallizes in the monoclinic crystal system, space group P21/n, as a dimer with a planar Al2I2 four-membered ring. The crystal structure of the monoclinic structure of Bu2GaI was redetermined. Its mass spectra reveal the existence of trimers and dimers in addition to the predominant monomeric species in gas phase.