The stoichiometric reactions of N-(2-methylquinolin-8-yl) (R)amides (L1-L8; L1, R = Ph; L2, R = p-FPh; L3, R = p-ClPh; L4, R = p-(MeO)Ph; L5, R = o-MePh; L6, R = p-MePh; L7, R = Me; L8, R = CF3) with Me3Al afforded the corresponding dimethylaluminum amidate complexes [Me2AlL] (C1-C8). The treatment of N-(2-methylquinolin-8-yl)picolinamide (L9) with 1 or 2 equiv of Me3Al formed Me(2)AlL9 (C9) or Me(2)AlL9 center dot Me(3)A1 (C10), respectively; meanwhile, the stoichiometric reaction of L9 with iBu(3)Al gave iBu(2)AlL9 (C11). All organoaluminum amidate complexes were fully characterized by H-1/C-13 NMR spectroscopy and elemental analysis, and the unambiguous structures of complexes C2, C4, C9, and C11 were further determined by single-crystal X-ay diffraction. With the assistance of 1 equiv of BnOH, all dialkylaluminum amidate complexes showed appreciable activities toward the ring-opening polymerization of epsilon-caprolactone and produced polycaprolactones with narrow polydispersity; the nature of the active species was also investigated.