Some new tetrahydrobenzoquinazolinediones 2a-4a, tetrahydrobenzocycloheptenuracils 5a, 6a and their thioxo analogues 2b-6b were synthesized within a project aimed at obtaining new HIV-1 tricyclic inhibitors whose scaffold includes a pyrimidine and a phenyl ring, which are present in various HIV-1 non-nucleoside inhibitors. Among the tetrahydrobenzoquinazolinediones 2a-4a, compounds 3a and 4a, in which the tricyclic system is respectively in an angular or linear arrangement, proved to possess a HIV-1 inhibitory activity which was in the micromolar range, while compound 2a, in which the tricyclic system is in the angular arrangement opposite to that of 3a, was found to be completely inactive. As regards the tetrahydrobenzocycloheptenuracil derivatives (5a and 6a), only 5a showed an inhibitory activity similar to that of 3a and 4a. Furthermore, all thioxo analogues 2b-6b were found to be devoid of any activity.