*2.1. Synthetic Methods*

All starting materials were obtained from commercial sources and were used without further purification. Cyclotricatechylene was prepared as previously described [23].

[Cs((CH3)2CO)6][K4(H6ctc)4(H2O)8][Cs4(H2O)6](PO4)3 (**III**) was prepared by dissolving 24 mg (0.065 mmol) of H6ctc in 3 mL of acetone and adding 14.8 mg (0.065 mmol) of K2HPO4 in 1 mL of water followed by 9.7 mg (0.065 mmol) of CsOH in 2 mL of water. Multi-faceted crystals formed and were collected by filtration; yield 30.5 mg (51%). Analysis: Found (%): C 39.6, H 4.5; calculated (%): C 39.8, 4.5.

[Rb((CH3)2CO)6][Rb2K2(H6ctc)4(H2O)6][Rb4(H2O)6](PO4)3 (**IV**) was prepared by dissolving 24 mg (0.065 mmol) of H6ctc in 3 mL of acetone and adding 14.8 mg (0.065 mmol) of K2HPO4 in 1 mL of water followed by 6.7 mg (0.065 mmol) of RbOH in 2 mL of water. Multi-faceted crystals formed, which appeared, by visual inspection, to be homogenous in the mother liquor however the solid product underwent considerable deterioration during the attempted filtration of the crystals.

[Cs((CH3)2CO)6][K4(H6ctc)4(H2O)8][Cs(H2O)9](SO4)3 (**V**) was prepared by dissolving 24 mg (0.065 mmol) of H6ctc in 3 mL of acetone and adding 8.9 mg (0.065 mmol) of KHSO4 in 1 mL of water followed by 9.7 mg (0.065 mmol) of CsOH in 2 mL of water. Multi-faceted crystals formed and were collected by filtration; yield 19.0 mg (41%). Analysis: Found (%): C 45.4, H 4.5; calculated (%): C 44.8, 5.2.

[Rb((CH3)2CO)6][Rb2K2(H6ctc)4(H2O)6][Rb(H2O)9](SO4)3 (**VI**) was prepared by dissolving 24 mg (0.065 mmol) of H6ctc in 3 mL of acetone and adding 8.9 mg (0.065 mmol) of KHSO4 in 1 mL of water followed by 6.7 mg (0.065 mmol) of RbOH in 2 mL of water. Multi-faceted crystals formed, however upon filtration significant deterioration of the solid was noted. A solid yield of 17 mg was recorded but analysis indicated the product was inconsistent with the single crystal X-ray analysis.
