This study reports the first demonstration of the sequential cyclodehydrogenation 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.

Isabelle Kolly, Gema Navarro-Marín, Robert Häner, Silvio Decurtins, Ernst Meyer, Ulrich Aschauer, Rémy Pawlak, Shi-Xia Liu, Small Science2026, 6, e70288