The conductivity of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic) acid (PEDOT-PSS) thin-films was increased by up to 900 times with the addition of linear-diols. Three series of linear-diols were investigated. It is proposed that three mechanisms contribute to improved conductivity, conformational changes in the polymer from coil to expanded, spatial separation of PEDOT-PSS grains and charge screening. The variation in conductivity with temperature indicates that diols affect both intra- and inter-chain charge transports. Electrochromic devices were constructed using standard and enhanced conductivity PEDOT-PSS. Switching times from bleached to darkened states were reduced while darkened to bleached states remained unaltered. Total percent transmission change (%Delta Tx) remained constant indicating that enhanced conductivity PEDOT-PSS improves switching but does not lead to additional electrochromic redox sites being accessed. (c) 2008 Elsevier B.V. All rights reserved.