Free-radical photopolymerization enables rapid, spatially localized solidification and is essential to UV inkjet printing, additive manufacturing, and coating technologies. However, despite the precise spatiotemporal control inherent to the process, the interaction of complex reaction kinetics and coupled multiphysics impedes the development of high-fidelity models. This complexity obscures the full behavioral profile of the process; consequently, achieving consistent curing and predictable mechanical properties on the feature scale remains a persistent challenge. Many existing modeling approaches describe the photopolymerization process using reaction–diffusion equations combined with kinetic mechanisms. Although successful in capturing certain phenomenological behaviors, such models are often constructed with implicit or weak coupling between the underlying physical mechanisms. Furthermore, the thermodynamic basis of the coupled system is not always made explicit, particularly regarding the driving forces at smaller length scales. In this work, we develop a continuum-scale multiphysics framework for photopolymerization that is grounded in thermodynamic consistency. The formulation is based on the principles of entropy and energy, deriving the coupled evolution of reaction, diffusion, and deformation from these fundamental quantities. Species mobility is modeled using Flory–Huggins-type thermodynamic relations, providing a physically motivated driving force for diffusion. In addition, the evolution of the crosslink density is described explicitly to enable coupling between the chemical model and the mechanical response. To solve this strongly coupled system, the governing equations are formulated in weak form and solved using isogeometric analysis. The computational implementation is carried out using the open-source Nutils framework. At the conference, we will present the theoretical formulation, numerical implementation, and illustrative simulation results that demonstrate the structure and capabilities of the proposed modeling approach.