New bis-nucleophilic precursors to [1.4]oxazepines synthesized via S _N Ar-Smiles rearrangement-S _N Ar cascade have been designed. Employing them in base-promoted condensation with aromatic bis-electrophiles allowed differentiating between highly and poorly reactive substrates (i.e. those which can and cannot pass through the Smiles rearrangement barrier, respectively). The reactivity toward the desired course of cyclization can be restored by introducing electron-withdrawing substituents in the bis-electrophile precursor. This strongly argues for the importance of the Smiles rearrangement for the successful overall ring formation.