Herein, a new series of regio-random polythiophene polymers were synthesized by partially substituting non-alkylated furan unit into the conjugated backbone in order to enhance the inter and intra-molecular interactions of polymers. The systematic tuning of monomer ratio revealed the dramatic effects of furan substitution on the charge transport ability of polymers. The optimized polymer showed an enhanced of over 3 cm2 V -1 s -1 in electrolyte-gated organic field-effect transistors compared to the control polymer without furan substitution (~2 cm2 V -1 s -1). Moreover, when the synthesized polymers were incorporated as hole transport materials for AgBiS2 nanocrystal solar cells, the optimized polymer showed a high power conversion efficiency of over 6%. This study will provide a new insight into improving the crystallinity of random polymers for high performance solution-processable electronics.