The ionic interaction complexation between metal carboxylated polystyrene ionomers and poly(butyl methacrylate-co-vinyl pyridine) (BVP) in both solution and bulk was studied by viscometry, laser light scattering (LLS) and differential scanning calorimetry (DSC) and compared with that between BVP and carboxylated polystyrene (CPS), in which the interacting groups are in acid form. The results show that both kinds of complexation strongly depend on the level of the specific interaction and give rise to an increased hydrodynamic radius over the component polymer coils. However, the ionic interaction complexation generally results in an increased viscosity in the solution and almost always exhibits two glass transition temperatures (T(g)s), in contrast, the hydrogen bonding complexation leads to a decreased viscosity and only one T-g. The different behavior is attributed to the difference in spatial distributions of the interacting sites in the complexes.