Me 2 AlCl, Et 2 AlBr, and i Bu 2 AlCl react with (dpp-BIAN)Na (dpp-BIAN ) 1,2-bis [(2,6diisopropylphenyl)imino]acenaphthene) in Et 2 O to give the dialkylaluminum complexes (dpp-BIAN)AlR 2 (R ) Me (1), Et (2), i Bu (3)). Compounds 1-3 have been characterized by elemental analysis, IR and ESR spectroscopy, and X-ray crystal structure analysis. In the molecules of 1-3 the Al atoms are tetrahedrally coordinated by two alkyl groups and the two N atoms of the dpp-BIAN ligand. The ESR spectra of the complexes prove the radical character of the dpp-BIAN ligand and show a hyperfine structure due to the coupling of the unpaired electron with the 14 N, 27 Al, and 1 H nuclei.