The dilithium complex of N,N′-bis(2,6-diisopropylphenyl)-o-phenylenediamide, [Li₂L(thf)₃], reacts with TaMe₃Cl₂ in THF/Et₂O to yield [Li(Et₂O)(thf)LTaMe₃Cl] in which the phenylene backbone of L²⁻ is bound η⁴ to the Ta centre. This dinuclear species reacts with MeLi to yield the tetramethyltantalum complex [Li(Et₂O)(thf)LTaMe₄]. Double deprotonation of N,N′-bis(2,6-diisopropylphenyl)(4,5-dimethyl)-o-phenylenediamine (H₂L′) in Et₂O yielded the dilithium complex [Li₂L′(OEt₂)₂]. The two additional methyl groups on L′²⁻ change the observed reactivity towards TaMe₃Cl₂: rather than bridging between Ta and Li, ligand oxidation occurs to afford mononuclear [LiL′(OEt₂)]. This monolithium radical species, which was characterized by EPR spectroscopy, can also be synthesized using the more conventional oxidant AgBF₄. Double deprotonation of H₂L with KCH₂Ph in toluene followed by reaction with TaMe₃Cl₂ furnished [TaLMe₃]. Preliminary reactivity studies show [TaLMe₃] reacts with unsaturated substrates N,N′-dicyclohexylcarbodiimide and mesityl azide to undergo migratory insertion into one of the Ta–C bonds: the corresponding amidinate and triazenido ligands are generated. When subjected to UV irradiation, [TaLMe₃] undergoes reduction accompanied by loss of a methyl group to yield the dimeric species [TaLMe₂]₂.