Dynamic covalent chemistries (DCCs) offer huge potential to build function into biomaterials. By facilitating the reorganization of covalent bonds in a crosslinked network, dynamic chemistries have been tuned to imbue materials with valuable properties such as tissue-like viscoelasticity, responsive drug delivery characteristics, and stimuli induced degradation. The thioester exchange is a newly developed DCC that, through it’s widely tunable kinetics and compatibility with conventional photopolymerizations, offers great potential. My project focuses on the study of how thioester exchange chemistry can be used to develop cytocompatible hydrogels with viscoelastic and mechanical properties that can be tuned through external stimuli like light and thiol species. Combined with the photoinitiated thiol-ene photopolymerization, thioester exchange chemistry can be a powerful new tool to in the development of biomimetic viscoelastic hydrogels, and stimuli induced degradable biomaterials.