Nine anionic water-soluble calix[4]arene species, incorporating sulfonate, carboxylate or phosphonate groups, six of them incorporating two 2,2'-bithiazole subunits in alternate position at the lower rim, have been synthesised and evaluated as anti-HIV agents on various HIV strains and cells of the lymphocytic lineage (HIV-1 III B/MT4, HIV-1 LAI/CEM-SS, HIV-1 Bal/PBMC), using AZT as reference compound. A toxicity was detected for a minority of compounds on PBMC whereas for the others no cellular toxicity was measured at concentrations up to 100 microM. Most of the compounds have an antiviral activity in a 10-50 microM range, and one of them, sulfonylated, displays its activity, whatever the tropism of the virus, at a micromolar concentration.