The electrochemical carbon dioxide reduction reaction (CO2RR) is attractive in terms of resolving the ever-growing release of CO2 from anthropogenic cause. Thereby, electrochemical CO2RR combines high energy-transfer yields and the refinement to versatile products such as C1- chemicals, which represent the concurrent carbon feedstock. Herein we explore the CO2 reducing property of nanofibrous chalcopyrite copper indium sulfide CuInS2 (CIS) and the pristine cobalt oxide (Co3O4), both p-type semiconducting materials, towards CO production mainly with remarkable faradaic efficiencies of 77% and 65%, respectively [1]. The focus in our studies are given to the utilization of the nanofiber electrodes as an appropriate electrocatalyst for CO production without using further expensive metal supplements, e.g. palladium, platinum, and potassium. Thus, the nanocrystalline shaping of nanofiber networks was achieved by the low-cost, versatile and time-saving electrospinning technique. In order to reduce the imperfection in the crystalline fiber, Polyacrylonitrile (PAN) was selected as template polymer [2]. The desired chemical structure of nanofibers was achieved through sintering process at 500 °C and 550 °C, respectively. With reasonable product selectivity by CuInS2 and pristine Co3O4 nanofibers [3] and a stable operation at a constant electrolysis potential for many hours, we think that this work will stimulate more exploration into using nanofiber based materials in energy recovery and carbon capture and utilization technologies. [1] Aljabour A.; Coskun H.; Apaydin D.H.; Ozel F.; Hassel A.W.; Stadler P.; Sariciftci N.S.; Kus M.; Applied Catalysis B: Environmental; 229; 2018; 163–170. [2] Ozel F.; Kus, M.; Yar, A.; Arkan, E.; Yigit, M. Z; Aljabour, A.; Büyükcelebi, S.; Tozlu, C.; Ersoz M, Materials Letters. 2015, 140, 23–26. [3] Aljabour A.; Apaydin D.H.; Halime Coskun, Ozel F.; Ersoz M.; Stadler P.; Sariciftci N.S.; Kus M.; ACS Appl. Mater. Interfaces 2016, 8, 31695−31701.