Figure 1.

A) Aromatic region of variable‐temperature ¹H NMR spectra of mPHBC 8 (500 MHz, 273 K and 298 K in CD₂Cl₂, 313–373 K in C₂D₂Cl₄); B) aromatic region of ¹H NMR spectra of HBC precursor 14, dianion 15 (300 MHz) and pPHBC 16 at 298 K and 213 K (500 MHz, [D₈]THF). The height of the solvent residual peaks was normalized for comparison.