The electrochemical reductions of 9 benzo[b]naphtho[2,3-d]furan-6,11-dione derivatives in dimethylformamide were investigated. In the aprotic medium the quinones reduced in two successive one-electron steps. The influence of molecular structure on reduction potential is addressed. The reduction process involved a single irreversible two-electron process in the presence of a proton source, occurring via an ECE mechanism. A relationship is observed between reduction potential and reported inhibitory activity against various cancer cell lines. The hydroxyl substituted derivatives exhibit the most positive E(1/2) values and have generally more potent activities.