Synthesis and Reactivity of Dithienopyrazines**

Heteroacenes developed to widely used building blocks in organic semiconductors for application in organic electronics due to their tunable structures and properties concomitant with inherent stability. Here, we report efficient preparation and investigation of so far unknown heterotriacenes, basic anti ‐ and syn ‐dithienopyrazine 5 and 6 . The comparison of the two isomers with respect to electronic properties and follow‐up reactions gives insights into structure‐property and ‐reactivity relationships. Examples of transition metal‐catalyzed C−C cross‐coupling reactions of corresponding halogenated derivatives show the practical impact for extended π‐conjugated systems applied in optoelectronic devices.