The oxo-bridged diiron(III) complex [{Fe(L-his)(dpq)}2(μ-O)]2+ having L-histidine (L-his) and dipyrido[3,2-d:2′,3′-f]quinoxaline (dpq) bound to Fe(III) exemplifies an iron-based model photonuclease that shows visible light-induced DNA double-strand cleavage in a photodecarboxylation pathway and models iron–bleomycin activity.