Photochemical addition of furan derivatives to fullerene C-60 was applied to the photo-crosslinking of polymers with C-60 A polymer having furan units in the side chains was synthesized by the reaction of poly(2-hydroxyethylmethacrylate) with 2-furoic chloride. A 1,1,2,2-tetrachloroethane solution of the polymer was exposed to visible light in the presence of C-60 The solution turned to a gel after 10 h and then solidified completely. The photo-crosslinking process was monitored in situ by dynamic viscoelasticity measurement.