The glass-transition temperature (T-g) of pyridine-soluble extracts obtained from Upper Freeport (UPF) coal was investigated. Previous studies have suggested that such a transition, if it exists, might occur at high temperatures and is probably masked by other transition processes. In this study, we used differential scanning calorimetry (DSC) experiments to calculate that the glass transition of the UPF coal extract occurs at similar to194 degreesC. This T-g value was obtained using an extrapolation of observed T-g values of miscible blends of the coal extract and poly(4-vinylpyridine) (P4VPy). UPF extract/P4VPy blends were prepared as a series that had a UPF extract content of 10-85 wt %. DSC thermograms of all blends exhibited a single T-g value at a temperature higher than that of pure P4VPy. The T-g values of the blends were dependent on the composition of the coal extract. Using the Kwei equation, which describes the relationship between blend composition and T-g, the T-g value of the coal extract was calculated.