“…Over the past century, Bischler‐ Napieralski cyclization has provided an efficient way to access libraries of structurally diversified nitrogen‐containing heterocyclic compounds with potential pharmaceutical or biological activities. [ 8‐9 ] For example, various benzodiazepines derivatives were obtained, such as pyrrolobenzo[ b ]thieno[1,4]diazepines, [ 10 ] tricyclic pyrimido[4,5‐ b ][1,4]benzothiazepines, [ 11 ] 5 H ‐[1]benzofuro[2,3‐ d ][1,2]diazepines, [ 12 ] 11 H ‐pyrimido[4,5‐ b ][1,4]benzodiazepines [ 13 ] and pyrrolo[1,2‐ a ][1,6]benzodiazonines. [ 14 ] Despite the high efficiency in C=N bond formation within aromatic rings via Bischler‐Napieralski cyclization, its utility in synthesizing aza‐PAHs was not recognized until 2010.…”