A new series of intramolecular bridged alkylcobaloxime complexes were prepared by heating a solution of aqua(3-bromopropyl)cobaloxime (1) through an intramolecular nucleophilic substitution. They are characterized by EA, ESI-MS, and H-1 NMR. Crystal structures of Br(O-C3H6-(dmgH))(dmgH)Co-III (2), [H2O(O-C3H6-(dmg))(dmgH(2))Co-III]ClO4 (3), [Py(O-C3H6-(dmg))(dmgH(2))Co-III]ClO4 (4), [Bzm(O-C3H6-(dmg))(dmgH(2))Co-III]ClO4 (5), and Im(OC3H6-(dmg))(dmgH)Co-III (6') were determined by X-ray diffraction. It is revealed that an intramolecular tri-methylene bridge exists between cobalt and one of the equatorial oxime oxygens forming a six-membered ring in the complexes. Additionally, the axial bases have some influences in their structure parameters, for example, Co-L bond lengths; folding angles in equatorial ligands; hydrogen atom positions in O-H-O bridge; and the orientations of those L planes with respect to the equatorial planes.