To study the phase transition of copper (II) phthalocyanine (Cu-Pe) thin films, we measured the surface resistance using a near-field scanning microwave microscope (NSMM) by measuring the microwave reflection coefficient S-11. The crystal structure of Cu-Pe thin films transformed from the a-phase of the orthorhombic crystal to the thermally stable beta-phase of the monoclinic crystal as the substrate heating temperatures increased. The surface resistance depended on the crystal structures of the Cu-Pc thin films. As the phase changed from the alpha-phase to the beta-phase, the surface resistance of the Cu-Pe thin films decreased. (c) 2005 Elsevier B.V. All rights reserved.