Facile synthesis of polyethers of the type (A-O)n( )is achieved by triphenylmethyl (trityl) perchlorate-catalyzed reductive condensation of dialdehydes with triethylsilane, and the method was also extended to the synthesis of polyethers of the type (A-O-B-O)(n) by the reductive polycondensation of dialdehydes and alkylene bis(trimethylsilyl) ethers. The reductive polycondensation of isophthalaldehyde (1a) proceeded even at -50 degrees C to yield the polyether consisting of one unit derived from 1a. Dialdehydes with weak electron-withdrawing groups such as ester, carbonate, and bromide also underwent the reductive polycondensation to yield the corresponding polyethers having such functional groups. Especially, bis(4-formylphenyl) succinate (1b) resulted in the polyether with the highest molecular weight of dialdehydes investigated. The reductive,polycondensations of dialdehydes 1 and alkylene bis(trimethylsilyl) ethers 2 were carried out with dimethylphenylsilane to yield the polyethers consisting of alternating 1 and 2 units. Primary and secondary 2 were effective for obtaining polyethers of the type (A-O-B-O)(n) by the reductive polycondensation of 1 and 2.