We synthesized Fe(II)-based metallo-supramolecular polymers with bisterpyridines bearing ethynylene, phenylene, and durene as spacer (polyFeL1-3) and investigated the effect of the spacer modification on the electrochromic properties. We revealed the redox potential and MLCT absorption of polymers were greatly influenced by the spacer alteration. PolyFeL1-3 exhibited different colors; blue, bluish purple, and purple, respectively. Blue- and purple-colored electrochromic devices were successfully fabricated using polyFeL1 and polyFeL3. The electrochromic color changes were observed upon applying +3V for bleaching or -3V for coloring.