We designed and synthesized air- and moisture-stable gallafluorenes in which two benzene rings were bridged by the four-coordinate gallium atoms. The series of gallafluorenes were prepared by introducing electron-donating and -withdrawing groups through Suzuki-Miyaura coupling reactions. The gallafluorenes showed unique emissions via their triplet states in the presence of B(C6F5)(3). These emissions were obtained via the triplet exciplex of gallafluorene and B(C6F5)(3).