Pyromellitic‐Diimide‐Based Liquid Material Forming an Exciplex with Naphthalene

Abstract We report a liquid material based on a pyromellitic diimide (PMDI) framework with branched alkyl chains for the first time. An electron‐accepting PMDI‐based liquid can dissolve electron‐donating solid naphthalene. This liquid demonstrates green photoluminescence (PL) originating from exciplex formation, the properties of which are different from those of the PMDI‐based liquid and naphthalene. The photophysical behavior was investigated by measuring PL spectra and undertaking excited‐state decay measurements.