Single crystal polarized electronic spectra and paramagnetic susceptibilities throughout the temperature range 20–300 K are reported for the complexes [M(H 2O) 2(tdmmb)][BF 4] 2; M = Ni(II, Co(II); tdmmb = 7,15-dihydro-7,9,13,15-tetramethylpyrido-[2′,1′,6′:12,13,14][1,2,4,7,9,10,13]-heptaazacyclopentadeca [3,4,5,6,7,8- aklmn][1,10] phenanthroline. The electronic properties of these formally pentagonal bipyramidal macrocyclic, complexes are analysed within a global, axial model — shown to be wholely inappropriate for the nickel complex — and within the angular overlap model. The ligand fields are dominated by the phenanthroline-type ligator as a strong σ donor and π donor, presumably reflecting the presence of electron rich nitrogen atoms substituted in the phenanthroline aortho positions. By contrast the two imine groups of the macrocycle act as a weak σ donors in line with the much longer MN bond lengths. Despite the ligand field asymmetry in the macrocycle plane, the molecular magnetic susceptibility tensor is calculated to be essentially axial with respect to the normal to this plane.