Certain naphthalenesulfonic acid analogues have been synthesized and evaluated for their inhibitory effects on HIV-1- and HIV-2-induced cytopathogenicity, HIV-1 giant cell formation, and HIV-1 reverse transcriptase (RT) activity. A bis(naphthalenedisulfonic acid) derivative having a biphenyl spacer emerged as the most potent and selective inhibitor of virus-induced cytopathogenicity in MT-4 cells. The ED50 values for this compound were 7.6 and 36 microM for HIV-1 and HIV-2, respectively. No toxicity to the host cells was detected at 98 microM. This compound also inhibited giant cell formation and was superseded in potency by a bis(naphthalenedisulfonic acid) derivative having a flexible decamethylene spacer. In the cell-free RT assay, a long-chain amide derivative exhibited the most inhibition of RT. All the compounds that achieved complete inhibition of virus-induced cytopathogenicity at concentrations not toxic to host cells were derivatives of 4-amino-5-hydroxy-2,7- naphthalenedisulfonic acid. These analogues represent new leads for the development of anti-HIV agents.