Organic polymers possessing a conjugated p-electron system have fascinated scientists all over the world because of their electronic and physical properties. These nanostructured polymers have received great attention because of their potential application in electronic displays, electrode materials in batteries, semiconductors, sensors, capacitors, molecular electronic circuit elements, and secondary batteries. [1][2][3][4][5] Optoelectronic devices often require polymeric transparent electrodes to improve their performance and to create devices with only polymer components. [6][7][8][9] Poly(3,4-ethylenedioxythiophene) (PEDOT) can be a good material for optoelectronic devices because of its high conductivity, narrow band gap, good stability at ambient conditions, and film-forming properties. For applications requiring both conductivity and good optical/electrical properties, it can be blended with tougher insulating polymer matrices, resulting in mechanically resistant and easy-to-process conducting polymer blends. [10,11] In these blends, conductivity is achieved by percolation of the dispersed conducting polymer phase hosted in an insulating polymer matrix and by spin-coating or casting for film formation. However, only thin films of conducting polymers can be fabricated with these procedures, and the film morphologies are unstable when processed at temperatures above the glass transition temperature (T g ) of the matrix polymer. In addition, they have not been extensively used as organic electronic devices because their electrical conductivity and electronic mobilities are not quite sufficient. To overcome these drawbacks, we propose a new and different concept for producing doped p-conjugated polymer films that are stable at high temperatures, highly conductive, and highly transparent at the nanoscale by relying on a continuous process that does not use any matrix or binder polymers. By using this new procedure, we can also easily realize well-defined thin films that are crystalline with fine-pitched patterns.In this Communication, we report for the first time on the self-assembly of ultrathin conducting films of PEDOT having a polycrystalline structure prepared by using vapor-phase polymerization. The vapor-phase polymerization technique is a bottom-up processing method that utilizes the organic arrangement of macromolecules to easily produce ordered aggregates, including on the nanoscale, or prepare thin films of self-assembled molecules, micropatterns, or modified microstructures of pure conducting polymers, as shown in Scheme 1. The PEDOT-patterned films can be formed by microcontact printing [12,13] using the selective self-assembly of 3,4-ethylenedioxythiophene (EDOT) monomers. By using this method, several kinds of conductive PEDOT structures were assembled on a substrate film, and the thickness of the assembled PEDOT layer and the height of the grown pattern were easily controlled between 20 and 300 nm with a 3 lm pitch by varying deposition temperature and time in the vapor deposition chamber. (1) ...