1 Department of Chemistry, McGill University 801 Sherbrooke St. W H3A 0B8 Montreal Canada tomislav.friscic@mcgill.ca.
2 FRQNT Quebec Centre for Advanced Materials (QCAM/CQMF) Montreal Canada.
3 School of Chemistry, Cardiff University Main Building. Park Place Cardiff CF10 3AT UK.
4 Faculty of Chemistry, University of Warsaw 1 Pasteura St 02-093 Warsaw Poland.
5 Department of Biochemistry and Chemistry, Concordia University 7141 Sherbrooke St. W H4B 1R6 Montreal Canada.
6 International Institute for Nanotechnology, Department of Chemistry, Northwestern University 2145 Sheridan Road 60208 Evanston Il USA.

Mechanochemistry enables rapid access to boron imidazolate frameworks (BIFs), including ultralight materials based on Li and Cu(i) nodes, as well as new, previously unexplored systems based on Ag(i) nodes. Compared to solution methods, mechanochemistry is faster, provides materials with improved porosity, and replaces harsh reactants (e.g. n-butylithium) with simpler and safer oxides, carbonates or hydroxides. Periodic density-functional theory (DFT) calculations on polymorphic pairs of BIFs based on Li⁺, Cu⁺ and Ag⁺ nodes reveals that heavy-atom nodes increase the stability of the open SOD-framework relative to the non-porous dia-polymorph.