The complexes {(C5H8O2)2Zr[(OCH3)2B(C6H5)2]2.1/2C12H10} (M = Zr (1) or Hf (2)) have been obtained from the reaction of [M(acac)3Cl] with sodium tetraphenylborate (BPh4(-)) in methanol. Crystal structures show 8-coordinate complexes with two 2,4-pentanedionato groups and two dimethoxydiphenylborate groups each coordinated through methoxy groups to the metal centre.