A diamine monomer (4,4΄-(((5,11-dihydroindolo[3,2-b]carbazole-6,12-diyl)bis(4,1-phenyl-ene))bis(oxy))dianiline) containing a rigid conjugated indolocarbazole was designed and synthesized through a three-step reaction. A series of high-performance functional polyimides were prepared through simple condensation polymerization of the monomer with different industrial dianhydrides 6FDA, BTDA and ODPA, respectively, which exhibit superior thermal stability, good solubility in polar organic solvents and good mechanical properties. The glass transition temperature (T_g) is above 334 °C, and the 5% weight loss temperature (T_d5%) of polyimides under nitrogen atmosphere falls in the range of 502~526 °C. The tensile strength and tensile modulus are 49.45~60.08 MPa and 1.4~1.6 GPa, respectively. In addition, the maximum fluorescence emission wavelength of polyimides in the NMP solution (0.02 mg/mL) are around 448 nm with blue light emission and 451 nm as film without significant red shift, which indicates the prepared polyimides process a certain application potential in high-performance flexible polymer optoelectronic devices.