The reaction kinetics of the co-network formation was followed by in situ 1 H NMR spectroscopy in THF-d8 at 𝜙 = 0.06 and T= 25, 40, and 60 °C, respectively. For the measurements, stock solutions of 3 and 5 were prepared and combined with an equimolar ratio of reactive groups in a 5 mm NMR tube using a glass syringe and a precision balance. The tube was then sealed with a rubber septum, shaken sufficiently and immediately placed in the pre-heated NMR probe. After reaching the reaction temperature within approximately 5 min, the measurements were started. 98%) of both protons occurs. Errors result mainly from the signal overlaps that occur at higher conversions, since the network formation leads to significant line broadening.