Converting aggregation-induced emission of N-BF2 merocyanines to colour-tunable ultralong room temperature phosphorescence via Dexter triplet energy transfer: circumventing restriction of intersystem crossing

The pure π–π* transition-based molecular design along with embedded intramolecular interactions and structural diversity endowed the guest N-BF 2 merocyanines with long τ P s, good Φ P s, and phosphorescence colour tunability via a simple TTET mechanism.