The ligand 1,2-bis(benzimidazol-2-yl)ethane (1a) and its N,N′-dioctyl (1b), N,N′-bis(3,5-dimethoxybenzyl) (1c) and 5,5′-dimethyl-N,N′-diethyl (1d) derivatives have been prepared. With MCl₂ the ligands give complexes [MLCl₂] (M=Mn, Fe, Co, Ni, Cu, Zn) which generally appear to have tetrahedral coordination geometry. X-ray crystal structures of [Cu(1c)Cl₂]·MeCN, [Cu(1c)Br₂] and [Mn(1d)Cl₂]·MeCN have been determined, and show tetrahedral coordination of the metal, the copper(II) complexes showing significant distortion from ideal tetrahedral character. Comparison with other results in the literature, coupled with simple molecular mechanics calculations, suggests that the tetrahedral character may be favoured by the seven-membered chelate ring in which puckering is limited by the presence of two double bonds in the ring.