Room-temperature phosphorescence (RTP) materials have potential applications in anticounterfeiting, biochemistry, and optical recording. It is significant to develop a novel approach to enriching RTP materials. Here two new hybrid RTP solids were obtained by the introduction of organic 1,3,5-tris(1-imidazolyl)benzene and halogen atoms to simultaneously coordinate with inorganic moieties. Single-crystal X-ray analysis reveals that Br atoms are oriented toward the adjacent organic molecules that can play an important heavy-atom effect (HAE). Notably, such a HAE realized by orienting the Br atom to the location immediately adjacent to the triplets produced can efficiently facilitate intersystem crossing and results in RTP with intensity similar to that of the fluorescence in steady-state photoluminescence.