Poly(2-vinyl pyridine) [P2VP] and poly(4-vinyl pyridine) [P4VP]/copper iodide binary mixtures were studied by differential scanning calorimetry (DSC) in order to investigate the phase behavior of the blends at microscopic level. The glass transition temperature (T-g) of the P2VP/copper iodide binary mixtures as compared with pure polymer increased by 80 degrees C when the amount of Cu(I) in the blend was increased up to 40/60 wt/wt monomer/ inorganic salt composition for P2VP. For P4VP, the T-g increased by 40 degrees C in an 80/20 wt/wt decreasing by 10 degrees C at 60/40 wt/wt. Fourier transform infrared (FTIR) and Raman spectroscopy provided molecular-level data, suggesting that copper coordinates with pyridine rings via nitrogen ion pairs in a metal-ligand bonding. Conductivity measurements were carried out at different temperatures and compositions, and upon increasing the amount of copper iodine in the blends, the conductivity increased drastically.