Four analogues of the antitumour antibiotics, netropsin and distamycin, containing 2-nitroimidazole or 5-nitrofuran moieties were synthesised. All showed high affinity for DNA, including compounds with only one pyrrole/amidine moiety, but the radiosensitizing efficiencies were poor. The results have implications both for minor groove targeting and the design of radiosensitizers.