The use of the (NBu4)(2)[(ReCl4)-Cl-IV(ox)] mononuclear species as a ligand toward divalent first row transition metal ions in the presence of imidazole affords the new trinuclear compounds of formula (NBu4)(2)[{(ReCl4)-Cl-IV(mu-ox)}(2)M-II(Him)(2)] [NBu4+ = tetra-n-butylammonium cation, ox = oxalate dianion, Him = imidazole; M = Mn (1), Co (2), Ni (3), Cu (4)] whose preparation, crystal structures, and magnetic properties are reported. 1-4 are isostructural complexes which are made up of discrete trinuclear [{(ReCl4)-Cl-IV(mu-ox)}(2)M-II(Him)(2)](2-) anions and bulky NBu4+ cations. The Re and M atoms exhibit somewhat distorted octahedral surroundings which are built by four chloro and two oxalate oxygens (Re) and two imidazole nitrogen and four oxalate oxygen atoms (M), the central M atom being linked to the two peripheral Re atoms through bis-bidentate oxalate. The values of the Re center dot center dot center dot M separation across bridging oxalate vary in the range 5.646(2) (M = Ni) to 5.794(2) angstrom (M = Mn). Magnetic susceptibility measurements on polycrystalline samples of 1-4 in the temperature range 1.9-300 K show the occurrence of significant intramolecular antiferro- (1) and ferromagnetic (2-4) interactions. The nature and magnitude of the magnetic coupling in 1-4 are qualitatively understood through orbital symmetry considerations.