A series of novel benzimidazolones and their analogues, characterized by the presence of one or more methyl groups or other bioisosteric moieties at different positions of the phenyl ring at N-1, were synthesized and evaluated as inhibitors of human immunodeficiency virus type-1 (HIV-1). Most of the new compounds proved to be highly effective in inhibiting both HIV-1 replication in MT4 cells with minimal cytotoxicity and RT enzyme at nanomolar concentrations. Some derivatives were also tested against RTs containing single amino acid mutations responsible for resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs). The different potencies displayed by the new compounds were studied using molecular modeling.