Polybenzborimidazolines

Three new benzborimidazoline polymers have been prepared by condensation of aromatic diboronic acid derivatives and 3,3′‐diaminobenzidine. All of the polymers were soluble and had inherent viscosities in the range 0.1–0.35. The polymers prepared from benzene diboronic esters showed good thermal stability up to 500–600°C. A polymer prepared from ferrocene diboronic acid or ester began to decompose extensively between 300 and 400°C.