Optical absorption and emission, vibrational (resonance Raman) and electrochemical data of Ru(NH₃)₂Cl₂(bqdi) are described (bqdi = o-benzoquinonediimine). We explore the nature of the ruthenium benzoquinone electronic interaction in this species primarily within the framework of density functional theory (DFT) but also using INDO to extract Coulombic (J) and exchange (K) integrals. The resonance Raman and emission data were understood in terms of a common set of coupled vibrations localized primarily within the ruthenium metallacycle ring. Experimental and computational data were also compared among a select group of ruthenium bqdi species with other spectator ligands, specifically ammonia, 2,2'-bipyridine and 2,4-pentanedione. The detailed changes in the electrochemistry, optical spectroscopy and vibrational spectra with changing spectator ligand donicity were coherently explained within a common theoretical (DFT) model which further provided a detailed analysis of the variation in the molecular orbital descriptions. With the application of an extended charge decomposition analysis (ECDA) a detailed picture emerged of the bonding between the bqdi ligand and the ruthenium fragment, illustrating the coupling between the MOs of each fragment as a function of orbital symmetry and electron transfer between the fragments of the complex. Metal-to-bqdi ligand Π-back donation is seen to be very important. Aspects of more general utility to the physical inorganic community, are presented.