The reaction of EuOCl (EuCl 3 ) with dibenzoylmethane (HDBM) in the presence of N-methylmorpholine yields a novel Eu 5 square-pyramid polynuclear complex with a rare μ 4 -OH bridging mode, Eu 5 (μ 4 -OH)(μ 3 -OH) 4 (μ-DBM) 4 (DBM) 6 (1). The compound was characterized by elemental analysis, IR, fluorescence and Mossbauer spectra as well as by an X-ray single crystal structure determination. Crystallographic data for 1, C 1 5 0 H 1 1 5 Eu 5 O 2 5 , monoclinic, P2 1 /c, a=22.223(5), b=17.427(1), c=35.708(5) 9, β=100.11(2) o , V=13614(4) 9 3 , Z=4, R 1 =0.0979, wR 2 =0.1695.