A direct photopatterning of a vapor polymerizable and photo cross-linkable 3,4-ethylenedioxythiophene (EDOT) was investigated in order to make it suitable for use in electronics applications. As a patternable and conductive polymer, PEDOT-MA was synthesized using vapor phase polymerization (VPP) of the (2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl) methyl methacrylate (EDOT-MA). The transparency of the conductive films was tuned using the vapor polymerization time to control the film thickness. The photo reaction of the poly(EDOT-MA)by UV light allowed for a conductivity change from 30 S/cm to 1.67 x10^(-3) S/cm due to the photo cross-linking of the side chain. Such photochemically induced conductivity change of the PEDOT-MA film ensured a flexible conductive pattern on a flexible polymer substrate. The mechanism of the photo-induced conductivity change can be explained by the change in electron hopping due to the twisting of the main chain accompanied by side chain cross-linking. The photo cross-linking reaction of the side chain generated micro patterns having line widths of 900 nm, in which the light-exposed areas appeared as bleached and less conductive. From this mechanism and method the flexible conductive polymer pattern was obtained and flexible electrochromic display could be fabricated.