A ligand(N-APTH) and Co(II)complex compound of bidentate ligand which contains a ring of the pyrimidine have been produced. For the optical transmission measurements of the Co(II)complex compound thin films, a UV-Visible (UV-Vis) spectrophotometer was employed. As a result of optical measurements. it was revealed that Co(II)complex compound tends to show a semiconductor characteristic with the bandgap value of 3.46 eV. An attempt has been made to explore the rectifying and ohmic properties of Al/Co(II)complex compound/Cu structures assuming that Co(II)complex compound may exhibit a rectifier or ohmic behavior, depending on the fabrication process, when brought into an appropriate contact with a metal. From current-voltage (I-V) measurements, it was found that the device could show good ohmic and rectifying properties intentionally depending on the experimental process followed during fabrication. (C) 2010 Published by Elsevier B.V.