The heteronuclear Au-I/Hg-II complexes [Hg{AuR(mu-2-C6H4PPh2)}(2)] ER = C6F5 (1), C6Cl2F3 (2)] were prepared by reacting [Hg(2-C6H4PPh2)(2)] with [AuR(tht)] (1:2) and further transformed into the AuIII/HgII species [Hg{Au(C6F5)Cl-2(mu-2-C6H4PPh2)}(2)] [R = C6F5 (3), C6Cl2F3 (4)] by the addition of 2 equiv of PhI Cl-2. The crystal structures of 1-3 display Au center dot center dot center dot Hg-II interactions, which in the case of 3 is the first Au-III center dot center dot center dot Hg-II contact described to date. Theoretical calculations on model systems of the C6F5 derivatives evidence that the attraction between Au-I or Au-III and Hg-II arise from dispersion-type interactions and that both contacts are of the same strength.