Palladium mediated hydrolysis of coordinated acetonitrile in the complex [Pd(phen)(MeCN) 2 ](BF 4 ) 2 , under basic conditions, affords the dinuclear palladium(II) species bis(μ-acetamido-O,N) {bis[(1,10-phenanthroline)palladium(II)]}bis-tetrafluoroborate.X-ray crystallographic analysis of this species (structure a) and of its acetonitrile solvate (structure b) shows that the syn isomer of the complex is formed and that dimers aggregate to form discrete tetrameric units (Pd–Pd intradimer distances 2.875(3)Å (a), 2.852(1)Å (b) and Pd–Pd* interdimer distances 3.213(3)Å (a), 3.079(1)Å (b)). The correlation between syn-coordination mode and aggregation of dimers is discussed.