The photo-induced copolymerization of electron donor/electron acceptor monomers has been studied by real-time infrared spectroscopy. With maleimide/vinyl ether mixtures, the reaction was found to proceed rapidly upon u.v. exposure in the absence of oxygen to reach nearly 100% conversion within seconds. The two monomers disappeared at similar rates, with formation of an alternating copolymer. Similar results were obtained with maleimide/N-vinylpyrrolidone and maleimide/styryloxy combinations. Highly crosslinked polymer networks have been produced by photo-induced copolymerization of bis-maleimide and divinyl ether monomers. These photoinitiator-free formulations were found to be less sensitive to oxygen inhibition than typical u.v.-curable acrylate resins. N-substituted maleimides were also shown to act as monomeric photoinitiators by inducing the polymerization of acrylate monomers upon u.v. irradiation.