Starting materials were mixed and spectra collected prior to milling (figure ). They display a very similar profile to 2-methylimidazole (figure ), indicating that most of the hydrogen signal is coming from that reactant. The plot of the ZIF-8 product (figure ) consists of two distinct peaks. The T1 values are similar at 10.4 s and 0.83 s, with T2* values of 175 µs and 14 µs. The main signal, with the shorter T2*, indicates the formation of ZIF-8. The sharp signal towards the top of the plot is evidence of water and acetic acid formed as by-products in the reaction. This is supported by figure , which shows the product after rinsing and drying overnight under vacuum where the liquid peak is no longer visible. The remaining signal has very similar relaxation time values as the previous plot. The relaxation time values for all these samples are summarized in table S1 in the supplementary information.