In this review, PEDOT-PSS is mainly a commercially available PEDOT-PSS, which is a water-dispersible form of the intrinsically conducting PEDOT doped with the water-soluble PSS, including its derivatives, copolymers, analogs (PEDOT:PSSs), even their composites via the chemical or physical modification toward the structure of PEDOT and/or PSS. First, we will focus on discussing the scientific importance of PEDOT-PSS in conjunction with its extraordinary properties and broad multidisciplinary applications in organic/polymeric electronics and optoelectronics from the viewpoint of the historical development and the promising application of representative ECPs. Subsequently, versatile film-forming techniques for the preparation of PEDOT-PSS film electrode were described in details, including common coating approaches and printing techniques, and many emerging preparative methods were mentioned. Then challenges (e.g., conductivity, stability in Water, adhesion to substrate electrode) of PEDOT-PSS film electrode for devices under the high humidity/watery circumstances, especially electrochemical devices are discussed. Fourth, we take PEDOT-PSS film electrode for a relatively new application in sensors as an example, mainly summarized advances in the development of various sensors based on PEDOT-PSSs and their composites in combination with its preparative methods and extraordinary properties. Finally, we give the outlook of PEDOT-PSS for possible applications with the emphasis on PEDOT-PSS film electrode for electrochemical devices, including sensors. (c) 2016 Wiley Periodicals, Inc.