Similar efficient worked the extension of the basic structure with ethynyl groups and TMS-protected acetylene 33 was subjected to Sonogashira-Hagihara-type coupling reactions with the same brominated syn-dithienopyrazines 14, 15, and 18. Bis(triphenylphosphine)palladium(II) chloride (Pd (PPh3)2Cl2) and copper iodide were used as catalytic system and triethylamine and toluene served as solvent. For this type of cross-coupling reaction we noted differences in reactivity, whereby the '-dibrominated dithienopyrazine 18 was substantially more reactive than the '-dibrominated derivative 14. 2,6-Diethynylated derivative 34 was isolated in 96% and the reaction was completed after 18 hours at room temperature, the 3,5-diethynylated isomer 35 was isolated in 68% yield after reaction at 50 °C and 48 hours reaction time. Tetrabrominated dithienopyrazine 15 needed harsher reaction conditions (24 hrs at 110 °C) to provide tetraethynylated derivative 36 in 70% yield (Scheme 9). These transition metal-catalyzed Suzuki and Sonogashira-type coupling reactions, which were optimized for the brominated syn-dithienothiophenes 14, 15, and 18, were as well applied to the corresponding anti-derivatives 16, 17, and 21 in order to prepare series of triarylamino-functionalized dithienothiophenes as potential hole-transport materials for perovskite solar cells. The results will be reported in a forthcoming paper.