The reaction between cis-[Ru(dmso)Cl2] (dmso=dimethylsulfoxide) and the macrocycle 1,4,7,10-tetrathiacyclododecane ([12]aneS4) gives the complex cation [Ru([12]aneS4)(dmso)Cl]+. A new series of RuII([12]aneS4) complexes were obtained by replacing the dmso and the chlorine ligands with polypyridylic or related monodentate ligands. Complexes with the general formula [Ru([12]aneS4)(L)]2+, where L=bidentate ligand: dipyridylamine (dipa); 5-phenyl-1,10-phenanthroline (5-phen); 1,10-phenanthroline-5,6-dione (5,6-dione); o-phenylenediamine (pda) or 4,4′-diphenyl-2,2′-dipyridyl (dbp) have been synthesised. Related complexes containing monodentate ligands, [Ru([12]aneS4)(CH3CN)Cl]+, [Ru([12]aneS4)(CH3CN)2]2+ and [Ru([12]aneS4)(ind)Cl)]+ (ind=indazole) were also prepared. The complexes were characterised by NMR, UV/Vis and IR spectroscopy and their electrochemical behaviour was studied by cyclic voltammetry. The X-ray single crystal diffraction structures of the complexes [Ru([12]aneS4)(dmso)Cl]Cl, [Ru([12]aneS4)(CH3CN)2][PF6]2, [Ru([12]aneS4)(CH3CN)Cl]PF6, [Ru([12]aneS4)(5,6-dione)][PF6]2·2CH3CN, [Ru([12]aneS4)(5-phen)][PF6]2 and [Ru([12]aneS4)(ind)Cl]PF6·CH3CN were determined. All complexes exhibit a distorted cis-octahedral environment with the macrocycle adopting a folded conformation.