The preparations and properties of bis complexes of ruthenium(II) containing various combinations of the tridentate ligands 2,6-bis(pyrazol-1-ylmethyl)pyridine (L¹) and di- and tetra-methyl substituted derivatives (L² and L³) are described. The absorption spectral properties of the complexes are thoroughly analysed. Full assignments have been made for the ¹H NMR spectra of two representative complexes in CD₃CN and the origins of the co-ordination-induced shifts are discussed. Cyclic voltammetric experiments (MeCN solutions) reveal reversible one-electron Ru^III–Ru^II redox couples in the potential range 1.00–1.06 V vs. saturated calomel electrode (SCE). The occurrence of ligand-based irreversible reductions at low potentials (E_p,c values lie in the range: –1.90 to –2.20 V vs. SCE) reveals that these pyrazole-rich ligands are very poor π acceptors. The formal potentials of the Ru^III–Ru^II couples decrease (by ca. 8 mV per methyl group) as the number of methyl groups in the ligands are increased. The decreased potential step size for [RuL(L′)]²⁺(L,L′= L¹–L³) relative to those observed for non-sterically hindered ruthenium(II) complexes reveals that in the present system steric effects due to 3-Me substituent(s) contribute to the observed effect but that electronic factors predominate over steric effects.