In this manuscript, the authors reported a series of pyridinium salts with room-temperature phosphorescence and microsecond radiative lifetime. Through the regulation of anion(I-)-π(pyridinium+) distance, the RTP efficiency was up to as high as 93%. Correspondingly, this efficient RTP material could act as X-ray scintillating dye in neat film, showing great application value. Neverthelss, there are some concerns needing to be addressed before publish.
1. The RTP properties for these materials seemed to be studied under an inert atmosphere of argon. Then, how about the RTP performance in atmospheric environment?
2. Why were the radioluminescence spectra measured at 150 K? As the RTP efficiency of ion pair 2 is very high, the authors are suggested to study its RL property at room temperature. Also, the stability of RL upon continuous X-ray irradiation should be measured for practical applications.
3. In this manuscript, the I∙∙∙C distances were measured to evaluate the anion(I-)-π(pyridinium+) interactions in crystals, while SOC value should be directly related to the distance between the heavy atom and the center of a chromophore. Thus, the authors are suggested to re-measure the distances between I and the center of pyridinium in crystals, thus to better study its influence on ISC effect.
4. Some important references should be added, such as Prog. Mater. Sci. 2022, 125, 100914; Appl. Phys. Rev. 2022, 9, 011304; J. Am. Chem. Soc. 2025, 147, 2653; Aggregate 2024, 5, e462 and so on.

The manuscript has been largely improved after revisions