Three derivatives of thieno[3,2-b]thiophene end-capped with phenyl units have been synthesized and characterized by MALDI TOF mass spectroscopy, elemental analysis, UV-vis absorption spectroscopy and thermogravimetric analysis (TGA). All compounds were prepared using Pd-catalyzed Stille or Suzuki coupling reactions. Optical measurements and thermal analysis revealed that these compounds are promising candidates for p-type organic semiconductor applications.