Complexes of the general formula M(X-SALDAPE) and M(X-SALDAPS) formed by the reaction of substituted salicylaldehydes and bis(3,3'-aminopropyl)ether or bis(3,3'-aminopropyl)sulfide with nickel(II) and cobalt(II) have been isolated. The complexes have been characterized by elemental analysis, mass spectra, infrared spectra, magnetic susceptibility measurements, and ultraviolet-visible-near infrared spectra. In the solid state the nickel(II) complexes, Ni(X-SALDAPE) and Ni(X-SALDAPS), where X = H, 5-Br, 3-(CH₃)₂CH, or 3-CH₃O, are speculated as pseudo-square planar or weak low-spin five-coordinate structures. The complexes exhibit anomalous magnetic behavior explained in terms of a spin state isomerism between singlet and triplet spin states. In a non-coordinating solvent, the nickel complexes are pseudo-square planar losing all five-coordinate structural features due to salvation. When dissolved in a coordinating solvent, the complexes are high-spin pseudo-octahedral. The cobalt(II) complexes, Co(H-SALDAPE) and Co(X-SALDAPS) where X = H, or 3-(CH₃)₂CH, were found to be high-spin pseudo-tetrahedral in the solid state with magnetic moments of approximately 3.4 B.M. The olive green nickel complexes are stable to air and moisture. The brownish cobalt complexes are stable as dry solids, but very easily oxidized when wet. / Master of Science