Peropyrene (III) was synthesized via the diketone (II) and by reduction of peropyrenequinone (IV). The latter can also be obtained from the diketone (II). 4: 4′- Dibenzanthronyl gave 4: 4′-dibenzanthrenyl (V), the dehydrogenation of which yielded the yellow compound (VI) which displayed thermochomy involving the blue form (VIa). This decomposed to (VII). Condensation of benzanthrone with phosphorus oxychloride gave 4: ...