Treatment of the thiosemicarbazones 2-ClC 6 H 4 C(Me)NN(H)C(S)NHR, (R: Me, a; Et, b) and 2-BrC 6 H 4 C(Me)NN(H)C(S)NHR (R: Me, c; Et, d) with lithium tetrachloropalladate(II) in methanol or palladium(II) acetate in acetic acid gave the tetranuclear cyclometallated complexes [Pd{2-XC 6 H 3 C(Me)NNC(S)NHR}] 4 (X/R: Cl/Me, 1a; Cl/Et, 1b; Br/Me, 1c; Br/Et, 1d). Reaction of 1a–1d with bis(diphenylphosphino)methane, Ph 2 PCH 2 PPh 2 , in a 1:4 molar ratio and concentrated hydrochloric acid gave the mononuclear complexes [Pd{2-XC 6 H 3 C(Me)NN(H)–C(S)NHR}(Ph 2 PCH 2 PPh 2 -P,P)](Cl) (2a–2d). Reaction of 1a–1d with bis(diphenylphosphino)methane, Ph 2 PCH 2 PPh 2 , in 1:2 and 1:4 molar ratios gave the dinuclear or mononuclear complexes [{Pd[2-XC 6 H 3 C(Me)NNC(S)NHR]} 2 (μ-Ph 2 PCH 2 PPh 2 )] (3a–3d), and [Pd{2-XC 6 H 3 C(Me)NNC(S)NHR}(Ph 2 PCH 2 PPh 2 -P)] (4a–4d), with bridging and chelating diphosphine, respectively. The molecular structures of complexes 1b, 1d, 4c and 4d have been determined by X-ray diffraction analysis.