Fig. 4. (a) In situ EPR spectra measured every 10 minutes during light irradiation. Reaction conditions: 5 mg TTT–DTDA (COFs), 0.25 mL methyl methacrylate (MMA), 12.5 μL triethylamine (TEA) and UV-vis light irradiation using a 300 W Xe lamp with an output power 1.5 W. The inset image shows the light induced conversion of MMA to PMMA in the flat cell. (b) Proposed mechanism for free radical polymerization of MMA to PMMA using porous COFs, in presence of triethylamine as a co-initiator.