The peri interaction of 1-functionalized naphthalenes equipped with a triarylmethyl cation at the 8-position has been studied because of the reversibility of the ring-closing reaction, which was monitored closely by NMR spectroscopy in the case of the cyclic ammonium salt 5b. Carbocycle 4a and N-heterocycle 5b did not exhibit any tendency for ring cleavage under various conditions, whereas the naphtho-annulated