The absorption spectra, cyclic voltammetry and spectroelectrochemistry of [Ni II DPTAA] and [Co II DPTAA] (DPTAA=6,13-diphenyldibenzo[b,i][1,4,8,11]tetraaza[14]annulene) complexes in DMF are reported in detail. The ligand oxidation is observed for [Ni II DPTAA] at +0.70V vs. SCE whereas Ni 2+/+ occurs at −1.60V. For [Co II DPTAA], a ligand oxidation redox couple is seen at +0.56V while the Co 2+/+ and Co 2+/3+ redox couples appear at −1.21 and +0.24V, respectively. All observed redox couples are assigned to reversible one-electron processes on account of peak separations and scan-rate dependency. These processes were further investigated by spectroelectrochemistry for [Co II DPTAA]. For [Co II DPTAA], axial ligation of pyridine was found to shift the Co 2+/3+ redox couple more negative, while the ligand oxidation was shifted to more positive potentials. From a spectrophotometric titration of [Co II DPTAA] with pyridine an equilibrium constant, K f , was determined for the binding of pyridine to [Co II DPTAA]. This was found to be 10.2dm 3 mol −1 , slightly lower than that of [Co II TAA], indicating the influence of the phenyl groups. From this value and shifts in the Co 2+/3+ redox couple upon ligation, an equilibrium constant for the binding of pyridine to [Co III DPTAA], K f ′, was found to be 5.06×10 6 dm 3 mol −1 .