A new class of conjugated polycyclic molecules containing a C ₆ –C ₅ –C ₆ –C ₇ –C ₆ polycylic framework was synthesized. Both experiments and calculations show different electron structures in comparison to their pentacene isomers.

Post‐polymerization modification (PPM) via direct C−H functionalization is a powerful synthetic strategy to convert polymer feed‐stocks into value‐added products. We found that a metal‐free, Se‐catalyzed allylic C−H amination provided an efficient method for PPM of polynorbornenes (PNBs) produced via ring‐opening metathesis polymerization. Inherent to the mechanism of the allylic amination, PPM on PNBs preserved the alkene functional groups along the polymer backbone, while also avoiding transposition of the double bonds. Amination using a series of aryl sulfonamides led to good control over the degree of functionalization, access to a range of functionalities, and tunable thermal properties from the resulting polymers.