Ionic clusters as high-connectivity secondary building units for crystalline porous organic salts

Nature Chemistry, Published online: 08 September 2026; doi:10.1038/s41557-026-02248-w Rigid coordination bonds readily generate highly connected secondary building units in metal–organic frameworks, but weaker and less directional interactions have rarely afforded comparable architectures in molecular crystals. Now ammonium halide ion pairs are shown to aggregate into discrete clusters that function as soft secondary building units, opening a route to non-metallic organic frameworks with diverse topologies.