The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 19 . Thieno[3′,2′:4,5]thieno[2,3‐ c ]‐naphtho[1,2‐ f ]quinoline, thieno[3′,2′:4,5]thieno[2,3‐ c ]naphtho‐[1,2‐ f ][1,2,4]triazolo[4,3‐ a ]quinoline and thieno[3′,2′:4,5]‐thieno[2,3‐c]naphtho[1,2‐ f ]tetrazolo[1,5‐ a ]quinoline

Photocyclization of 3‐chloro‐N‐(3‐phenanthryl)thieno[2,3‐ b ]thiophene‐2‐carboxamide ( 5 ) yielded only one of the two possible structural isomers, thieno[3′,2′:4,5]thieno[2,3‐ c ]naphtho[1,2‐ f ]quinolin‐6(5 H )‐one ( 6 ), which was further elaborated to afford the unsubstituted ring system 10 , its triazole 11 and tetrazole 12 . The structural confirmation of 10 was achieved by the total assignment of its 1 H and 13 C nmr spectra by the concerted utilization of two‐dimensional nmr spectroscopic methods.