Photocrosslinkable prepolymers were synthesized by using poly(styrene-co-maleic anhydride) as the polymeric backbone and 4-[2-(4-[aminomethyl]phenyl)ethenyl]pyridine as the crosslinking agent. The photochemical [2+2] cycloaddition of the ethylene double-bond is utilized as the crosslinking principle. Using prepolymers, substituted with more than 2 mol% crosslinker, UV-irradiation yields insoluble networks. The network density can be easily adjusted by variation of the crosslinker content.