We present synthesis and characteristics of the conjugated polymers involving organogallium complexes. A series of alternating copolymers composed of gallafluorene were prepared with diverse comonomers through various types of cross-coupling reactions such as SuzukiMiyaura, Sonogashira-Hagihara, and Stille reactions. It was confirmed that the synthesized polymers possess solubility in common organic solvents and stability toward air and moisture. Significantly, optical properties originating from the electronic interaction between gallafluorene and various comonomers were observed. For example, vivid color emissions were demonstrated in the blue, green, yellow, orange, and red regions depending on the chemical structures of the comonomer units. In addition, it was eventually found that the benzotriazole-containing polymer showed significant optical properties originating from aggregation in the film state. From the electrochemical measurements, it was indicated that the energy levels of their frontier orbitals were varied by the comonomer units. Indeed, it is supported that the gallafluorene polymers have higher energy levels of HOMOs (highest occupied molecular orbitals) than those of the fluorene-based conjugated polymers instead of gallafluorene. Finally, it is suggested that the gallafluorene unit could work as an electron-donating group in the polymer main chain.