The tunability of organic room temperature phosphorescent (RTP) system is important but rarely reported. In this work, we report a series of host/guest ultralong organic room temperature phosphorescent materials with lifetime- and color-tuning properties. By doping a non-room temperature phosphorescence guest emitter 1, 8-Naphthalimide (NI) into a series of solid host matrices with higher triplet energy levels, the lifetime (0.20 s - 0.81 s) and color (yellow - green) of multiple RTP materials are realized. As the excitation wavelength is switched from 365 nm to 254 nm, the phosphorescent color changes significantly and the phosphorescent lifetime increases by a factor of almost two. Notably, the unique dual emission (fluorescence and phosphorescence) of the doped material 4BrBa-NI resulted in a different orange emission. The host/guest doping materials are prepared through co-crystallization or grinding, allowing for an efficient energy transfer from guest to host. The results indicate that strong intermolecular interactions and the intersystem crossing (ISC) ability of the guest play a significant role. In addition, the security protection and anti-counterfeit encryption applications for RTP materials are realized through various methods, such as handwritten pens, screen printing, and dynamic recognition of QR code, which significantly improves the commercial viability of the RTP materials.