Transition metal-catalyzed cross-coupling reactions of brominated syn-dithienopyrazines 14, 15, and 18. The application of the novel dithienopyrazines as building blocks in electronic organic materials requries efficient cross-coupling reactions in order to build up tailored -conjugated systems. In that respect, we elaborated the Pd-catalyzed Suzuki-type coupling of brominated syn-dithienopyrazines 14, 15, and 18 with TMS-substituted thiophene boronic ester 29 in order to elongate the dithienopyrazine system with additional thiophene units at different positions of the triacenes (Scheme 8). As catalytic system tris(dibenzylideneaceton)dipalladium (Pd2dba3) and tri-tert-butylphosphonium tetrafluoroborate [HP(t-Bu3)BF4] as ligand, and potassium carbonate as base was used in a mixture of THF and water. Dibromides 14 and 16 did not show differences in reactivity under the same reaction conditions (15 hr at r.t.). 3,5-Dithienylated dithienopyrazine 30 was isolated in 73% and the 2,6-disubstituted isomer 31 in 70% yield. The fourfold coupling reaction of tetrabrominated derivative 15 required somewhat more drastic conditions (22 hr at 60 °C) and delivered tetrathienylated 31 in 60% yield.