The facile synthesis of C-8 linked pyrrolobenzodiazepine–naphthalimide hybrid analogues is described. The compounds are prepared with varying degrees of linker length in order to probe the structural requirements for optimal in vitro anti-tumour activity. Some of these new hybrid compounds showed higher cytotoxic activity than the existing natural and synthetic pyrrolo [2, 1-c][1, 4] benzodiazepines.