Takaki Kanbara

Small molecules and polymers with conjugated structures can be used as organic optoelectronic materials. These molecules have conventionally been synthesized by cross‐coupling reactions; however, in recent years, direct functionalization of C−H bonds has been used to synthesize organic optoelectronic materials. Representative reactions include direct arylation reactions (C−H/C−X couplings, with X being halogen or pseudo‐halogen) and cross‐dehydrogenative coupling (C−H/C−H cross‐coupling) reactions. Although these reactions are convenient for short‐step synthesis, they require regioselectivity in the C−H bonds and suppression of undesired homo‐coupling side reactions. This review introduces examples of the synthesis of organic optoelectronic materials using two types of direct C−H functionalization reactions. In addition, we summarize our recent activities in the development of direct C−H functionalization reactions using fluorobenzenes as substrates. This review covers the reaction mechanism and material properties of the resulting products.