The compound 2,2′:6′,2″-terpyridine-4′(1′H)-thione 1 has been prepared and structurally characterised; in both the solid state and in solution, the thione tautomer is dominant. Compound 1 is a key entry into 4′-sulfur-functionalised tpy ligands and a representative alkylation with an electrophilic Fréchet dendrimer is presented and the structural characterisation of the new ligand 4 reported. Oxidation of 1 yields bis(2,2′:6′,2″-terpyridin-4′-yl)disulfide 2 which is a novel homoditopic tpy ligand and which forms a tetranuclear [4 + 4] iron(II) metallomacrocycle. Structural characterisation of 2 and preliminary data for the iron complex are presented.