Thermally rearranged polybenzoxazole (TR-PBO) hollow fiber membranes were prepared using a nonsolvent induced phase separation method intended to apply for CO2 separation from post-combustion flue gas. Asymmetric hollow fiber membranes were spun from a hydroxyl poly(amic acid) (HPAAc) precursor and subsequently converted to TR-PBO hollow fiber membranes after thermal treatment above 400 degrees C. The skin structure and porous substructure in TR-PBO hollow fiber membranes were maintained even after thermal treatment at above glass transition temperature (T-g) of precursor polymers. To fabricate defect-free hollow fiber membranes, the effects of dope composition and thermal rearrangement conditions were investigated. Gas permeation properties of TR-PBO hollow fiber membranes measured by constant pressure method with small laboratory scale test module revealed a high CO2 permeance (1940 GPU) with a CO2/N-2 selectivity of 13. (C) 2012 Elsevier B.V. All rights reserved.