In this study, the mechanical and thermal properties of amidoximated polyacrylonitrile fibers immobilized with iron(II) 2,2′-bipyridine complex (Fe(bpy)32+) have been investigated to support their commercial application for wastewater treatment. The mechanical properties were evaluated with respect to breaking strength and elongation at break in both dry and wet conditions. Dynamic mechanical analysis, differential scanning calorimetry, and thermogravimetric analysis techniques were used to determine the thermal behavior. The results indicate the effect of Fe(bpy)32+ immobilization on the breaking strength of the dry fiber samples were negligible, and the corresponding elongation at break decreased gradually with Fe(bpy)32+ content increasing. In addition, water treatment greatly affected the mechanical properties of the fibrous materials. Thermal studies reveal that Fe(bpy)32+ immobilization led to better fiber thermal stabilization in terms of higher storage modulus at high temperature regions, larger glass transition temperature, and smaller weight loss. The 2,2′-bipyridine ligands were found to be responsible for the better mechanical and thermal performance of the fibrous materials by enhancing the intermolecular crosslink. POLYM. ENG. SCI., 55:1052–1058, 2015. © 2014 Society of Plastics Engineers