The ability to fabricate multi-material thermoset with spatially controlled physical properties has been a challenge in traditional thermoset manufacturing. To address this challenge, we developed new photopolymerization methodologies that could selectively polymerize different monomers in one pot. Early on, we took advantage of a photoswitchable RAFT mechanism that could incorporate vinyl ethers and acrylates at growing polymer chain ends by switching the wavelength of light. The crosslink density could be temporally tuned by using different amount of light irradiation following the photo-controlled polymerization mechanism. By using photomasks, spatial control over the crosslink density was achieved on both macroscale and microscale. Later, we invented a new photopolymerization system that modulates a monochromatic light dosage to switch from radical to cationic polymerizations. By buffering the strong acid generation, we could incorporate acrylate and epoxide monomers selectively and tune the thermoset mechanical properties by only changing the amount of light irradiation. This methodology was also applied to switching two cationic polymerizations in one pot. Lastly in this thesis, we will discuss a hydrogen bond donor (HBD) catalyzed photoinitiated cationic polymerization from photoacid generators (PAGs). Through the formation of hydrogen bonds between a HBD and the coordinating anions in PAGs, the cationic polymer chain end propagations were significantly accelerated.