High quality polycrystalline polyaniline/7,7,8,8-tetracyanoquino-dimethane (PANI-TCNQ) complex thin films have been grown by vacuum evaporation. A scanning tunneling microscope, transmission electron microscopy and high resolution scanning electron microscopy characterized the films. The films showed totally different optical and electrical properties from both of PANI and TCNQ films. Unusual two-dimensional aggregates were observed in the films. A charge transfer phenomenon, from the PANI chains to the TCNQ molecules, was observed from the Fourier transfer infrared spectrum. Compared with that of PANI and TCNQ thin films, the structural and electrical properties of the PANI-TCNQ thin films are discussed.