Synthesis and characterization of seven ruthenium(II) and ruthenium(III) complexes of sulphoxide with 2-aminobenzimidazole are reported. Three different formulations exist; [cis-RuCl2(SO)3(2-ABZ)]; [trans-RuCl2(SO)3)(2-ABZ)]; and [trans-RuCl4(SO)(2-ABZ (where SO = dimethylsulphoxide(DMSO)/tetramethylenesulphoxide(TMSO); 2-ABZ = 2-aminobenzimidazole). These complexes are characterized by elemental analysis, conductivity magnetic susceptibility, 1H-NMR, 13C{1H}-NMR and electronic spectroscopy. †Dedicated to my teacher and mentor, Dr R.S. Srivastava, Associate Professor, University of Lousiana at Lafayette, USA.