The reactivity of benzo[1,2‐ b : 4,5‐ b ′]dithiophene‐4,8‐dione in Pd‐catalyzed C−H arylation was investigated. Using aryl bromides as aryl source in the presence of carbonate bases in 1,4‐dioxane, the mono‐C2‐arylated benzo[1,2‐ b : 4,5‐ b ′]dithiophene‐4,8‐diones were regioselectively obtained. This procedure allowed to introduce both electron‐rich and electron‐poor aryl substituents on the benzo[1,2‐ b : 4,5‐ b ′]dithiophene‐4,8‐dione unit. These conditions were also effective for the coupling with 1‐bromonaphthalene, 9‐bromophenanthrene as well as aryl bromides bearing synthetically useful nitrile, chloro and methoxy substituents. The photophysical properties of representative arylated compounds have been performed by joint experimental and theoretical studies.