Polymeric complexes formed between poly(4-vinylphenol) (PVPh) and poly(4-vinylphyridine) (PVP) at small molar ratio based on hydrogen bond in ethanol were found to undergo a long aging process during storage, which composed of two different stages. In Stage 1, the intra-complex reorganization occurred and the size of the complexes enlarged gradually. And in Stage 2, the aggregation between complexes particles occurred and made the size of the complexes enlarge more quickly. This aging process could last for 80 days even though the polymeric complexes precipitated in the end like others. The effect of aging time on the Layer-by-Layer assembly behavior of the complexes was also investigated. The assembly behavior of the complexes might change from linear growth to exponential growth by simply prolonging the aging time of the complexes and two extremely different structures were obtained. POLYM. ENG. SCI., 59:E394-E402, 2019. (c) 2018 Society of Plastics Engineers