The desirable properties of polymer-polymer blends have led to considerable research on transition-metal compatibilization of nitrogen-based and diene polymer blends. Polymers of interest are poly(vinylamine), poly(4-vinylpyridine), poly(ethyleneimine), poly(L-histidine), 1,2-polybutadiene and cis-polybutadiene. Binary polymer/transition-metal complexes exhibit synergistic thermal properties. The poly(vinylamine)/cobalt complex with 3 mol% cobalt showed a Tg enhancement of ≈ 140°C in comparison to the undiluted polymer. Binary mixtures of the polymers of interest are incompatible. It was attempted to compatibilize these blends with a transition-metal salt. Cobalt chloride hexahydrate successfully compatibilizes blends of poly(vinylamine) and poly(ethyleneimine).