The starting materials before milling included 0.75 mL of water, which is apparent in the 2D plot (figure ). Water has relatively long T1 and T2 * lifetimes due to significant mobility in the liquid state. The noted intermediate was captured after 30 minutes of milling (figure ). The water peak is still very evident, with new peaks appearing in the bottom corners of the plot. Formation of MOF-74 (figure ) shows multiple new peaks, attributed to assembly of the periodic porous solid. The T1 of the major peak on the upper left of the plot is at 12 ms. The T1 of the two peaks on the bottom are 0.20 s and 11.2 s. The T2* values are 7 µs, 7 µs and 106 µs. The smaller less intense peaks trailing off to the right at the longer T2* are most likely artifacts. Water adsorption of the porous Zn-MOF-74 product explains the change in the water peak. The relaxation time values for all these samples are summarized in Table in the supplementary information.