The recent emergence of organic electrochromics on both the scientific and industrial levels has expedited the synthesis of new materials with varied electrochemical and optical properties. The structural versatility and broad usage of poly(3,4-ethylenedioxythiophene) (PEDOT) has stimulated many research groups on the potential of PEDOT derivatives. Here we report the first synthesis of pentadecafluoro-octanic acid 2,3-dihydro-thieno(3,4-b)(1,4)dioxin-2-ylmethylester (EDOT-F) along with its electrochemical polymerization, characterization, and incorporation into electrochromic devices (ECDs). PEDOT-F is a cathodically coloring polymer that exhibits sub-second switching time between a dark-blue neutral state and transmissive sky-blue oxidized satae, and expresses a 63% change for both transmittance at lambda(max) and colorimetrically determined luminance. Hexafluorophosphate-doped free-standing films of PEDOT-F process conductivities of up to 65 S cm(-1). Variable transmittance ECDs constructed with PEDOT-F and poly[3,6-bis(2-(3,4-ethylenedioxythienyl))-N-methylcarbazole] (PBEDOT-NMeCz) exhibit an optical contrast of 60% at lambda(max) (580 nm) and an overall luminance change of 60%. Indicating the hydrophobicity of this polymer, doped PEDOT-F exhibits a water contact angle of 110degrees, significantly higher than the 30degrees exhibited for the doped PEDOT parent.