A crystalline bisindolylmaleimide with strong solid-state fluorescence of red color and its analogous cross-linked polymer without fluorescence

<p>A crystalline bisindolylmaleimide (BIM) <b>3</b> with strong fluorescence in the solid state was prepared and studied. Its analogous cross-linked polymer <b>4</b> with the same BIMs fluorophore was designed and characterized. The investigation of the covalent bonding networking effect on the solid-state fluorescence was carried out by the comparison between <b>3</b> and <b>4</b>.</p>