In this work, we report a novel and simple one-pot synthesis of substituted dibenzo[b,f]oxepines under transition-metal-free conditions. This cascade process involves nucleophilic aromatic substitution followed by Knoevanagel condensation, as evidenced by the isolated reaction intermediates. We have also achieved the synthesis of anticancer bauhinoxepin C in 7 steps with 5.1% overall yield using this synthetic approach.