Formation of Bundle Assemblies of Stereoregular Polymers in Thermal Solid-State Polymerization of 7,7,8,8-Tetrakis(aryloxy­carbonyl)‑<i>p</i>‑quino­dimethanes

7,7,8,8-Tetrakis­(aryloxycarbonyl)-<i>p</i>-quinodimethanes with bulky aryloxy groups such as benzyloxy (<b>1a</b>), pentafluoro­benzyloxy (<b>1b</b>), and both benzyloxy and pentafluoro­benzyloxy (<b>1c</b>) were synthesized. We investigated effects of these bulky groups on thermal solid-state polymerization reactivities on the basis of crystal structures of <b>1a</b>–<b>1c</b>. Thermal polymerizations gave 1,6-<i>trans</i>-type stereoregular polymers in quantitative yields in 1 day at 110 °C for <b>1a</b>, 1 day at 150 °C for <b>1b</b>, and 6 days at 110 °C for <b>1c</b>. Their initial crystal shapes were retained in appearance during polymerization to yield solid bundle assemblies of their polymeric chains. X-ray single-crystal structure analysis indicates that their crystals adopt molecular arrangements suitable for one-dimensional polymerization with the 1,6-<i>trans</i>-type addition along one crystallographic axis. Such arrangements led to expansion polymerization of <b>1b</b> and contraction one of <b>1c</b>. The resulting stereoregular polymers form less ordered bundle assemblies than those prepared by the conventional topochemical polymerization. In this manner, the bulky aryloxy groups enabled us to observe a close relation between the molecular assembly modes and the polymerization behaviors, providing the first example for proving diversity of thermal solid-state polymerizations.