Blends of poly(1-vinylimidazole) (PVI) and poly(p-vinylphenol) (PVPh) were cast from ethanol or N,N-dimethylformamide (DMF). All the blends are miscible based on the single glass transition temperature (T-g) criterion. The T-g values of the blends are higher than those calculated from linear additivity rule. Blends cast from ethanol show a larger positive deviation than those cast from DMF. The T-g-composition curves can be fitted by the Kwei equation. FTIR studies show the existence of a strong hydrogen-bonding interaction between PVI and PVPh.