Exploiting Cooperative Catalysis for the On‐Surface Synthesis of Linear Heteroaromatic Polymers via Selective C–H Activation

Regiospecific C−H activation is a promising approach to achieve extended polymers with tailored structures. While a recent on‐surface synthetic approach has enabled regioselective homocoupling of heteroaromatic molecules, only small oligomers have been achieved. Herein, selective C−H activation for dehydrogenative C−C couplings of hexaazatriphenylene by Scholl reaction is reported for the first time. By combining low‐temperature scanning tunneling microscopy (STM) and atomic force microscopy (AFM), we revealed the formation of one‐dimensional polymers with a double‐chain structure. The details of the growth process are rationalized by density functional theory (DFT) calculations, pointing out a cooperative catalytic action of Na and Ag adatoms in steering the C−H selectivity for the polymerization.