1 McGill University, Chemistry, CANADA.
2 Concordia University, Chemistry and Biochemistry, CANADA.
3 University of Birmingham, Chemistry, UNITED KINGDOM.
4 Bruker UK Ltd, Bruker UK Ltd, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND.
5 McGill University, Department of Chemistry, 801 Sherbrooke Street West, H3A 0B8, Montreal, CANADA.

We report a rapid, room-temperature mechanochemical synthesis of 2- and 3-dimensional boroxine covalent organic frameworks (COFs), enabled by using trimethylboroxine as a dehydrating additive to overcome the hydrolytic sensitivity of boroxine-based COFs. The resulting COFs display high porosity and crystallinity, with COF-102 being the first example of a mechanochemically prepared 3D COF, exhibiting a surface area of ca. 2,500 m2 g-1. Mechanochemistry enabled a >20-fold reduction in solvent use and ~100-fold reduction in reaction time compared with solvothermal methods, providing target COFs quantitatively with no additional work-up besides vacuum drying. Real-time Raman spectroscopy permitted the first quantitative kinetic analysis of COF mechanosynthesis, while transferring the reaction design to Resonant Acoustic Mixing (RAM) enabled synthesis of multi-gram amounts of the target COFs (tested up to 10 g).