A new macrocyclic vic-dioxime, 1,3-bis(benzo-7,9,13-trithia-1,4-dioxacyclopentadecane)-2-thioxo-4,5-bis(hydroxyimino)imidazoline (H2L) has been synthesized by reaction of (E,E)-dichloroglyoxime (3) with N, N'-bis(benzo-7,10,13-trithia-1,4-dioxa-cyclopentadecane)thiourea (2), which was prepared from 2,3-(4'-aminobenzo)-7,10,13-trithia-1,4-dioxacyclopentadecane and thiocarbonyldichloride. The mononuclear Ni(II) complex of H2L, [Ni(HL)(2)], (4) has been prepared by reaction of H2L with nickel(II) chloride hexahydrate. The mononuclear Co(III) complex of the dioxime [Co(HL)(2)P(Ph)(3)Cl] (5) has been isolated with triphenylphospine and chloride as axial ligands. In addition, a Co(III) complex containing the BF2+ bridged macrocycle [Co(LBF2)(2)P(Ph)(3)Cl] (6) was synthesized using a precursor hydrogen-bridged Co(III) complex via the template effect. The heterotrinuclear complex of the BF2+-capped Co(III) complex [Ag2Co(LBF2)(2)P(Ph)(3)Cl](CH3COO)(2) (7) has also been prepared by reaction of this complex with Ag(CH3COO). The structures of the dioxime and its complexes were identified by elemental analysis together with H-1 and C-13 NMR, 1R and mass spectral data.