Figure 1.

(a) Pentacene (with carbon positions numbered) and related derivatives relevant to its thermal reactivity. (b) Synchrotron powder X-ray diffraction (SXRD) patterns of pentacene heated at 300 °C for 0–300 h, showing the peaks arising from polymorphs of pentacene (so called “14.1 Å” and “14.4 Å” polymorphs), HBP and 2HP/P co-crystals. (c) The scheme of observed products from the heating of as-received pentacene.