Solid polymer electrolytes are still collecting attention today for development of safer Li-ion batteries. Introduction of boron moieties to electrolytes generally improves ion conductive properties of resultant electrolytes. Herein, we have undertaken dehydrocoupling reaction between glycerol (Gly)/triethylene glycol (TEG) and hydroborane to synthesize highly branched organoboron polymer electrolytes. Increase in amorphous nature of polymer due to branched structure improved the ionic conduction. This was supported from decreased Vogel-Fulcher-Tammann parameters corresponding to activation energy of ion transport in matrices. When Gly content was increased beyond [Gly]/[TEG] = 15%, ionic conductivity decreased due to decrease in solubility of the salt in organoboron polymer matrix.