ABSTRACT Achieving organic phosphorescence that remains stable at elevated temperatures is challenging because thermally activated molecular motions typically accelerate non‐radiative decay of triplet excitons. Here, we report a topology‐driven conformational constraint strategy to enable high‐temperature organic phosphorescence. A hydrogen‐bonded supramolecular framework constructed from melamine and terephthalic acid serves as a rigid scaffold that imposes topological confinement on embedded t