Abstract: It is emphasized that hetero- and heavy-atoms and specific inter-molecular interactions are essential for ultra-long organic room temperature phosphorescence (RTP), moreover, the RTP production dominantly requires high-energy UV light excitation. In the current work, we present that coronene (Cor) doped PMMA and PS can all emit bright and ultra-long RTP with lifetimes of 4.43 and 2.97 s in air under 365 nm light excitation, respectively. More significantly, it is first found that both Cor/PMMA and Cor/PS exhibit rare visible light excitability up to 500 nm, and their afterglows are naked-eye visible and the RTP lifetimes are up to 2.46 and 2.11 s under 440 nm light excitation, respectively. However, hetero- and heavy-atom-free Cor has neither common spin-orbital coupling nor visible light absorption band in polymer film, and Cor/PS is a full hydrocarbon system. Therefore, we propose that the multi-resonance effect and largely fused systems are responsible for the abundant triplet population and the visible light excitability, signifying the significant enhancement of direct S0‒T1 transition. This work demonstrates a fresh RTP material system and phenomenon and provides a new perspective of understanding organic triplet generation and radiation.
