Abstract We herein report the synthesis and structure of three amino alcohol modified aluminum oxide clusters (AlOCs), namely, Al6(μ3-O)2(DEA)4(OiPr)6 (AlOC-30, H2DEA = diethanolamine), Al6(μ3-O)2(DIPA)4(OEt)2(OiPr)4 (AlOC-31, H2DIPA = diisopropanolamine) and Al6(μ3-O)2(DEA)4(PBA-iPr)2(OEt)2(OiPr)2·2HOiPr (AlOC-32, H2PBA = phenylboronic acid). Structure analyses indicate that all of them are isostructural hexanuclear compounds made up of two Al3 units bridged by amino alcohols. Intriguingly, an in situ esterification process is found in AlOC-32. Such an in-situ esterification reaction is vital for the understanding of the hydrolysis and aggregation process of Al(III) ions.