Summary Aimed to be used in very specific applications, novel materials with properties different from those of their neat constituents, based on poly(styrene‐co‐itaconic acid) (PSIA‐x) and poly(ethylacrylate‐co‐4‐vinylpyridine) (PEA4VP‐y) of various compositions, prepared by free radical polymerization, were elaborated by simply mixing pairs of these copolymers in chloroform or THF used as a common solvent. The effective specific interactions that occurred between the two constituents of the blends, evidenced by FTIR spectroscopy, depended on the blend composition and controlled the morphology of the various elaborated materials. Their phase behavior and thermal properties, investigated by differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA), confirmed enhanced thermal stability of most of these materials and differences in their mechanism of degradation. Moreover, the apparent activation energies of thermal degradation of a specific blend system estimated using Tang's method also confirmed a change in the thermal behavior of these materials with blend composition.