A new macrocyclic vicinal dioxime, 5,6:9,10:13, 14-tribenzo-2,3-bis(hydroxyimino)- 1,4,8,11-tetraazacyclodecane (H2L) has been synthesized by the reaction of (E,E)-dichloroglyoxime with 2,3:6,7:10,11-tribenzo-1,5,8,11-tetraazadodecane (4), which was prepared by the reduction of 1,2-bis(o-nitrophenylaldimino) benzene (3). The mononuclear cobalt(III) complex (5) of the dioxime has been isolated with L' = pyridine, together with chlorine as axial ligand. In addition, cobalt(III) complex containing the BF2+ bridge macrocycle (6) was synthesized using a precursor hydrogen-bridged cobalt(III) complex via the template effect. The heterotrinuclear complex of the BF2+-capped cobalt(III) complex (7) has also been prepared by the reaction of this complex with CdCl2 .satisfies H2O. The structure of dioxime and its complexes were identified by using elemental analysis, H-1, C-13 NMR, IR and MS spectral data. (C) 1997 Elsevier Science Ltd.