3-Dodecylthiophene end-capped two monomers: 2,8-bis-(4-dodecyl-thiophen-2-yl)-dibenzothiophene (DBT-3DTh) and 2,8-bis-(4-dodecyl-thiophen-2-yl)-dibenzofuran (DBF-3DTh) were synthesized via Stille coupling reaction. Both monomers exhibited emission peaks at about 400 nm with fluorescence quantum yields ranging from 0.16 to 0.21. The corresponding electroactive polymers poly(2,8-bis-(4-dodecyl-thiophen-2-yl)dibenzothiophene) (PDBT-3DTh) and poly(2,8-bis-(4-dodecylthiophen-2-yl)-dibenzofuran) (PDBF-3DTh) were obtained by electropolymerization method and displayed good electrochemical stability. Both polymers switched between light gray in the neutral state and blue in the oxidized state. Kinetic investigations showed that PDBT-3DTh exhibited a maximum optical contrast (Delta T %) of 25.23% at 575 nm with the coloration efficiency (CE) of 196 cm(2) C-1. However, the electrochromic properties of PDBF-3DTh were inferior to PDBT-3DTh. Further detailed discussions with EDOT and 3-alkylthiophenes end-capped DBT/DBF hybrid electrochromic polymers were comparatively studied. (C) 2015 Wiley Periodicals, Inc.