A family of four metallo-organic derivatives of aluminium(III) [(L)Al(CH3COCHCOOCH3)] (1-4) were synthesized by treating Al(OPri)3 with methyl acetoacetate and tridentate Schiff's base chelating ligand H2Lx (H2L1 = C13H11NO2; H2L2 = C13H10NO2Br; H2L3 = C14H13NO3; H2L4 = C17H13NO2) in 1:1:1 stoichiometry using mixture of anhydrous ethanol and benzene as solvent. The yellow coloured solid compounds obtained were characterized by FTIR, elemental analysis and NMR (1H and 13C) spectra. Complexes 1, 2 and 3 appeared as adducts with one mole of ethanol. As both the ligands used were asymmetric, the two possible structural isomers were well evidenced from NMR (1H and 13C) analysis. Furthermore, all the four heteroleptic derivatives of aluminium(III) were systematically screened as catalysts in ring opening polymerization of ϵ-caprolactone. Derivative 4 bearing bulky Schiff's base ligand was not active in polymerizing ϵ-caprolactone. The molecular weights and the polydispersity index values of polymers prepared were acquired by GPC analysis. The superior catalytic activity of complex 2 was rationalized by the presence of strong electronegative bromine atom. © 2018 Chemical Publishing Co. All rights reserved.