4,6-Dinitro-1-tosylindoline prepared from trinitrotoluene undergoes base-catalyzed condensation with aromatic aldehydes. With salicylaldehyde and 2-hydroxynaphthalene-1-carbaldehyde, the condensation is accompanied by intramolecular nucleophilic substitution for one of the nitro groups to give benzo- and naphthooxepino[4,3,2-cd]indoles, respectively.