A convenient approach to ladder-type 6H-benzo[4',5']thieno[2',3':4,5]thieno[3,2-b]indoles, e.g., I (X-rays single crystal structure shown)​, bearing various substituents in both terminal benzene rings has been developed. The protocol suggested for prepg. these N,S-​heteroacenes is based on using easily available reagents, such as cinnamic acids and arylhydrazines, which can be involved in the Fischer indole synthesis, as the key step. A similar condensed system of 12H-​benzo[4'',​5'']​thieno[2'',3'':4',5']​thieno[2',3':4,5]​thieno[3,2-b]indole, bearing six rings, has also been obtained.