The transmetallation reaction of bis(8-dimethylaminonaphthyl)mercury, [Hg(dman)₂], with [PdCl₂(SEt₂)₂] or [{PdCl₂(PPh₃)}₂] and palladium acetate afforded, by transfer of the substituted naphthyl group from mercury, a high yield of monoarylated palladium compounds, [Pd(dman)-Cl(L)]. Although no reaction occurred between [Hg(dman)₂] and [PtCl₂(SEt₂)₂] or [{PtCl₂(PEt₃)}₂] the reaction between [Pt(dman)₂] and Hg(O₂CMe)₂ resulted in [Pt(dman)₂Hg(O₂CMe)₂] which contains an unsupported Pt–Hg bond. Transmetallation from bis(8-methoxynaphthyl)palladium to [PdL₂Cl₂][L₂= cyclo-octa-1,5-diene (cod); L = SEt₂ or PhCN], Li₂[PdCl₄], and HgX₂(X = O₂CMe or Cl) provided several new arylpalladium complexes originating from exchange of ligands between the metal centres. For one of these products, [{Pd(mxn)(O₂CMe)}₂](mxn = 8-methoxynaphthyl), the structure in the solid state was determined by X-ray crystallography [monoclinic, space group P2₁/n, a= 19.539(2), b= 9.396(2), c= 13.893(3)Å, β= 110.75(1)°]. It shows a dimeric molecule in which the square-planar co-ordinated palladium atoms are bridged by the acetato groups [Pd–O 2.11(1)Å(average)] and each mxn group is C,O-chelate bonded to one palladium centre [Pd–C 1.97(2)Å(average), Pd–O 2.10(2)Å(average)]. The molecule is folded such that the Pd ⋯ Pd distance is 2.842(4)Å with the two naphthyl rings facing each other.