The one-pot diastereoselective synthesis of new N-substituted octahydroacridines was successfully achieved via BiCl3-catalyzed intramolecular cationic imino Diels?Alder reaction in good yields employing N-protected anilines and (±)-citronellal as substrates under mild conditions. It was observed that bulky N-substituent groups (allyl, propargyl, and benzyl substituent) play a key role in the cis/trans ratio of the thus-formed octahydroacridines. Increasing bulkiness permits preferential formation of the trans-fused heterocycles. It was found that use of the N-benzyl group resulted in a highly diastereoselective process that gives easily separable trans-fused N-substituted octahydroacridines. The developed protocol was extended to involve the use of citronella essential oil from Cymbopogon nardus as a renewable source of these biologically important heterocyclic molecules.