Polyaryloxydiphenylsilanes were prepared from phosphorus-containing diols and diphenydichlorolsilane through solution polymerization. With a stoichiometric imbalance in feed monomers, the resulting polymers exhibited moderate melting points and good processing properties. The polymers prepared showed initial decomposition temperatures above 340°C, excellent thermal stability, high char yields at 850°C and very high limited oxygen index values of 56-59. The polymers' char yields and their (P þ Si) contents showed linear relationships.