Ultralong organic room-temperature phosphorescence (RTP) materials have attracted great attention recently due to its diverse application potentials. Several ultralong organic RTP materials mimicking the host-guest architecture of inorganic systems have been exploited successfully. However, complicated synthesis and high expenditure are still inevitable in these cases. Herein, we develop a series of novel host–guest organic phosphore systems, in which all chromophores are electron-rich, commercially available and halogen atom free. The maximum phosphorescence efficiency and the longest lifetime reach at 23.6% and 362 ms, respectively. Most importantly, experimental results and theoretical calculation indicate that the host molecules not only play a vital role in providing a rigid environment to suppress non-radiative decay of the guest, but also show a synergistic effect to the guest through Förster energy transfer (FERT). The commercial availability, facile preparation and unique properties also make these new host-guest materials an excellent candidate for anti-counterfeiting devices.