In stark contrast to cyclodehydrogenation (CDH) for constructing graphene nanoribbons through C─C or C─N bond formation, selective pyrrole cyclization via on‐surface chemistry remains exceptionally rare and largely unexplored. To the best of our knowledge, this study reports the first demonstration of the sequential CDH of phenyl‐substituted tetraazapyrene (TAP) derivatives on an Au(111) surface, providing the first access to tetraazadiindenopyrenes via selective pyrrole cyclization followed by C–C coupling. By varying the number and position of the phenyl substituents, we reveal how molecular geometry and aromaticity dictate the cyclization pathway, promoting C─N bond formation over the well‐established C–C coupling embedded within the TAP framework. Low‐temperature noncontact atomic force microscopy (nc‐AFM) and differential conductance spectroscopy, complemented by density functional theory (DFT) calculations, not only provide an unambiguous structural assignment of the final products but also offer mechanistic insight into the sequential C–N and C–C cyclization processes.
Kolly et al. (Fri,) studied this question.