While most commonly used as an ex-situ technique, Nuclear Magnetic Resonance Spectroscopy (NMR) has been explored as a method for monitoring chemical reactions in real-time. Performing reactions directly inside the spectrometer eliminates the need for sample transfer and can provide information about short-lived transient reactive intermediate species while utilizing the high spectral resolution and rich chemical information that NMR provides. In recent years, several innovative designs have been used to guide light into the spectrometer to monitor lightinduced chemical reactions. For example, Mills and coworkers. inserted a fiber optic cable directly into an NMR sample tube containing both the locking solvent, CD3CN, and the photo-sensitive system, oxygen-saturated toluene with a titania catalyst. Over a period of 3 h, concentrations of the different reagents, intermediates, products, and side products were monitored in real time, demonstrating the utility of in situ NMR in photochemistry. As another example, Wolff and coworkers. applied a similar in situ irradiation setup which allowed for time-domain measurements of spiropyran and its photo-induced metastable byproduct merocyanine, yielding kinetic quantities such as rate constants and half-lives. Beyond basic photochemical reactions, in situ NMR has also been used to monitor photopolymerization reactions. Dolinski and coworkers. utilized in situ NMR to study the photo-induced reaction of methyl acrylate in the presence of photo-catalyst and a chain transfer agent. By varying light intensities, linear rates of polymerization were observed as predicted by the steady-state assumption and used to determine polymerization rate constants.