Poly(5,6-difluoro-2,1,3-benzothiadiazole-alt-9,9-dioctylfluorene) was successfully synthesized via direct arylation polycondensation of 5,6-difluoro-2,1,3-benzothiadiazole and 2,7-dibromo-9,9-dioctylfluorene. The reaction conditions were optimized, and a polymer with number-average molecular weight (M_n) of 41,000 was obtained by using Pd(OAc)₂, P^tBu₂Me-HBF₄, pivalic acid, K₂CO₃, and toluene as catalyst, ligand, additive, base, and solvent, respectively. The polycondensation was also performed with 5,6-dioctyloxy-2,1,3-benzothiadiazole or 2,1,3-benzothiadiazole as the comonomer, and the results indicate that the introduction of electron-withdrawing fluorine atoms at the ortho-positions to the CH bonds is essential for the reactivity of the direct arylation. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2367–2374