Novel polymerized ionic liquids having an organoboron unit were prepared for the purpose of selective lithium cation transport. Hydroboration polymerization of 1,3-diallylimidazolium bromide and subsequent anion exchange reaction with LiTFSI [lithium bis(trifluoromethylsulfonyl)imide] afforded the corresponding organoboron polymer electrolytes in 89-81% yield. The structure of polymers was supported by H-1 and B-11 NMR spectra. After the addition of an equimolar amount of LiTFSI toward the organoboron unit, an ionic conductivity of 3.74 x 10(-5)-1.93 x 10(-5) S/cm was observed at 50 degrees C. The lithium transference number for these systems was 0.87-0.45 at 30 degrees C. This demonstrates that anion trapping of the organoboron unit works very effectively in IL-based matrices compared with polyether-type matrices.