The syntheses of some novel B-ring homocannabinoid derivatives 1, 2 and 4 and related lactones 3 and 5 are described. Compounds 1-5 are 6,7,8,9,10,11-hexahydrodibenz[b,d]oxepins. CNS structure-activity correlations were determined using 3 rodent models [septal lesioned rats, rat muricidal activity and mouse activity tests]. The potency and activity profile of these 7-membered ring compounds were compared with the corresponding 6-membered ring homologues. A possible separation of CNS activities was noted with compound 1. Unexpected pharmacological activity was discovered with lactone 3, which was about equipotent to l-.DELTA.9-tetrahydrocannabinol. Dimethylation at the 7 position decreased CNS activity when the 6 position was either a carbonyl or methylene group.