Stability test. To test the stability of the solid forms, all synthesized samples were kept under humid conditions (achieved by a saturated solution of Na2SO4, RH:91% at 28 °C) in a sealed box for 5 days, followed by collection of PXRD data. All of the studied samples exhibited the same PXRD patterns as synthesized, except for HTBZ-HMA (neat) that transformed to HTBZ-HMA (LAG) (Figure ). Thermal studies. The thermal properties of each salt were investigated using TGA and DSC techniques, as illustrated in Figures . The thermal decomposition temperature for each salt was estimated based on the onset of mass loss in the TGA curves (Figure ). It was observed that each salt exhibited lower thermal stability compared to the molecular form of TBZ (246 °C). HTBZ-SAC showed a slight decrease in thermal stability (242 °C), while HTBZ-HOX and HTBZ-HFU demonstrated a moderate decrease (234 and 217 °C, respectively). Notably, HTBZ-HMA (LAG) displayed a significant decrease in thermal stability (182 °C) . Their crystal structures can rationalize the difference in the thermal behavior of the salts. We hypothesize that the stark decrease in the thermal stability of HTBZ-HMA is a direct consequence of the unique crystal packing of this salt. In the structure of HTBZ-HMA, instead of π-π stacked HTBZ columns, layers of interchanging HTBZ and HMA ions are observed (Figure ). Such local structure results in weaker interactions between neighboring ions, hence lower thermal stability. A possible reason for the lower thermal stability of the salts compared to the TBZ was the lower degradation temperature of counter acids.