Crystallographic studies. The four TBZ salts subjected to crystallographic study share two common characteristics. Firstly, they exhibit a well-defined hydrogen bonding scheme between HTBZ and each acid that has donated a proton, as depicted in Figure . Secondly, the HTBZ cations, which are electron-rich and planar, are observed to stack through π-π interactions. In the cases of HTBZ-SAC, HTBZ-HFU, and HTBZ-HOX, the cations stack with their symmetrically equivalent counterparts. On the other hand, in HTBZ-HMA, the cations stack with planar and unsaturated cations. Specific structural details for each salt are presented below.