*3.1. Stability Studies*

After preparing slurries of the three new (lidhcl) phases, it can be clearly seen (Figure S2) that (lidhcl)2(res) and (lidhcl)2(hq) were stable after 24 h stirring in water but not (lidhcl)2(pyr), which transformed into a new phase that could not be structurally characterised but only identified as new form. Moreover, it was observed that crystal forms with (lid), compared to (lidhcl), drastically changed their colour (Figure S2), which is a clear indicative of their poor stability with respect to oxidation.

Supplementary experiments were performed to evaluate the stability of (lidhcl) forms, in ageing conditions (40 ◦C and 75% relative humidity), where it can be observed that all three (lidhcl) new forms were stable after 2 months in ageing conditions (Figure 2), which did not occur for (lid) forms, as can be easily seen from Figure S2.
