Poly(4-vinylpyridine) (P4VPy) was blended with the lithium or zinc salt of poly(styrenesulfonate) (PSSLi and PSSZn, respectively). P4VPy formed complexes with PSSZn but not with PSSLi in water/ethanol (2:1) solutions, indicating the presence of a strong interaction between PSSZn and P4VPy.. P4VPy is immiscible with PSSLi, as shown by the appearance of two glass transitions in each P4VPy/PSSLi blend. Fourier transform infrared spectroscopic measurements showed the development of a new pyridine ring mode in P4VPy/PSSZn complexes. X-ray photoelectron spectroscopic (XPS) studies showed the development of high-binding-energy (BE) N Is peaks in all the P4VPy/PSSZn complexes but not in the P4VPy/PSSLi blends. Interaction between P4VPy and Zn2+ is also evidenced by the development of a low-BE S 2p doublet in each complex. Therefore, XPS reveals the existence of coordination between Zn2+ and P4VPy but not between Li+ and P4VPy.