We have performed Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) studies on blends of poly(vinyl phenol) (PVPh) with poly(n-alkylene 2,6-naphthalates) containing alkylene units of different lengths. The results indicate that each poly(ethylene 2,6-naphthalate) (PEN) and poly(trimethylene 2,6-naphthalate) (PTN) blend with PVPh is immiscible or partially miscible, but blends of poly(butylene 2,6-naphthalate) (PBN) with PVPh are miscible over the whole range of compositions in the amorphous state. FTIR spectroscopic analysis confirmed that significant degree of intermolecular hydrogen bonding occurs between the PBN ester carbonyl groups and the PVPh hydroxyl groups. The large difference in the degree of mixing in these blend systems is described in terms of the effect that chain mobility has on the accessibility of the ester carbonyl functional groups toward the hydroxyl groups of PVPh, which in turn impacts the miscibility of these blends.