The n-type pi conjugated polymers with a 1,2,4-triazole ring substituted by a benzo-15 crown 5 ether (benzo15C5) subunit at the 4-position of the 1 2,4-triazole ring were synthesized by organometallic polycondensations The UV-vis spectra of the polymers exhibited absorption maxima (lambda(max) values) at a longer wavelength than that exhibited by 4-benzo 15C5-1,2,4 triazole (model-1) revealing that their pi conjugation system was expanded along the polymer chain The electric conductivity measurements suggested that model 1 formed inclusion adducts with 1 1 and 2 1 molar ratios with Na+ and K+, respectively Addition of KClO4 to the DMSO solutions of the polymers with the benzo15C5 subunit caused the formation of the 2 1 inclusion between the 15C5 ring and K+, this inclusion led to a bathochromic shift in lambda(max) of the polymers In addition, photoluminescence intensity of the polymers decreased after the addition of KClO4 to solution The polymers with the benzo15C5 subunit underwent an electrochemical reduction (n-doping), and the corresponding oxidation (n-dedoping) occurred at an unusually high potential in an acetonitrile solution of NaClO4, the factor responsible for the unusually high oxidation potential was the stabilized n-doping state that was attributed to the inclusion of Na+ in the 15C5 ring The electric conductivities of the polymers were increased by n-doping with sodium naphthalenide The polymers with the benzo15C5 subunit exhibited a considerably higher stability of the n doping state in air than did those without this subunit