Titanium(ii) solutions, prepared by dissolving titanium wire in triflic acid + HF, contain equimolar quantities of Ti(iv). These preparations react readily with oxidizing species such as VO2+, substituted benzoquinones, and the biguanide complex of Mn(iv). Reactions with excess Ti(ii) yield Ti(iii). Reductions of 1,4-benzoquinones and the Mn(iv) complex are catalyzed by added Ti(iv) but stoichiometry is unaffected. Rate laws for the Ti(iv)-catalyzed reactions are consistent with formation of a Ti II-TiIV complex (Kformation 4 × 10 2 M-1), which, in some cases, also partakes in contributing deprotonated and halogen-catalyzed paths. © The Royal Society of Chemistry.