A new strategy for the convergent synthesis of metallosupramolecular oligomers has been elaborated. The key step is the formation of the ligand-complexes[Ru(X-terpy)(dpqtpy)][PF₆]₂(X-terpy = terpy, eoterpy, cterpy or msterpy) from the reaction of [Ru(X-terpy)Cl₃] with 6′,6″-di(2-pyridyl)-2,2′ :4′,4″ :2″,2‴-quaterpyridine (dpqtpy) in ethane-1,2-diol. These complexes have one non-co-ordinated terpyridine (terpy) domain, and reacted instantaneously with iron(II) salts to give the heterotrinuclear complexes [(X-terpy)Ru(dpqtpy)Fe(dpqtpy)Ru(X-terpy)][PF₆]₆. Similar reactions with cobalt(II) acetate gave the paramagnetic d⁷ cobalt(II) complexes [(X-terpy)Ru(dpqtpy)Co(dpqtpy)Ru(X-terpy)][PF₆]₆ which may be oxidised to the kinetically inert diamagnetic d⁶ cobalt(III) complexes [(X-terpy)Ru(dpqtpy)Co(dpqtpy)Ru(X-terpy)][PF₆]₇. The reaction of [Ru(X-terpy)(dpqtpy)][PF₆]₂ with ‘RuCl₃·nH₂O’ yielded the homotrinuclear complex [(terpy)Ru(dpqtpy)Ru(dpqtpy)Ru(terpy)][PF₆]₆. The ruthenium–osmium heterodinuclear complex [(terpy)Ru(dpqtpy)Os(terpy)][PF₆]₄ was readily obtained from the reaction of [Ru(terpy)(dpqtpy)][PF₆]₂ with [Os(terpy)Cl₃]. Some representative mixed-ligand homodinuclear complexes [(X-terpy)Ru(dpqtpy)Ru(Y-terpy)][PF₆]₄ containing both electron-releasing and electron-withdrawing terminator ligands were prepared from the reaction of [Ru(X-terpy)(dpqtpy)][PF₆]₂ with an equimolar quantity of [Ru(Y-terpy)Cl₃]. The specific examples with mixed terminator ligands were [(terpy)Ru(dpqtpy)Ru(dmterpy)][PF₆]₄, [(terpy)Ru(dpqtpy)Ru(msterpy)][PF₆]₄ and [(dmterpy)Ru(dpqtpy)Ru(msterpy)][PF₆]₄. All of the compounds were fully characterised, and detailed spectroscopic, spectrometric and electrochemical studies are described.