The molecular structure and purity were confirmed by single-crystal X-ray diffraction, NMR spectroscopy. The absorption spectra of the solution guests almost completely overlap, while the corresponding ones in the solid state are different (Supplementary Figure ). This shows that the benzene rings at different positions have almost no effect on the energy levels of the molecules, but they will affect the arrangement of the molecules. But the guests have almost no emission activity at room temperature in the solution and solid state (Supplementary Figure ). The host BPO is directly purchased commercially and purified by twice column chromatography. Because BPO has low melting point (66-71°C), the doped materials can be fabricated by the melt-casting method. A series of the 5-QL/BPO doped materials with different guest-host molar ratios (1:10-1:100000) are prepared to screen the materials with best phosphorescence properties. All the 5-QL/BPO doped materials emit green phosphorescence with an emission wavelength of around 520 nm, and when the ratio is 1:1000, the material has the strongest emission intensity (Supplementary Figure ), which is in line with our previous work. Therefore, other six doped materials with a guest-host molar ratio of 1:1000 is selected as the research target.