The synthesis of a range of N-alkyl 1, 4-dihydro-1, 4-iminonaphthalenes (7- azabenzonorbornadienes) and reduced derivatives is described together with 1, 4-dihydro- 1, 4-and 9, 10-dihydro-9, 10-iminoanthracenes. VT NMR studies lead to unambiguous assignment of invertomer preferences; changes in the invertomer ratios and nitrogen inversion barriers are investigated as the electronic and steric environment is modified by ...