Solvent activity data were obtained for three alcohols (methanol, 2-propanol, tert-butyl alcohol) in 4-vinylpyridine (4VP)-based polymers using a classical isothermal gravimetric-sorption method. The polymers were linear poly(4-vinylpyridine) (M-w = 160 000), cross-linked poly(4-vinylpyridine) with 2 and 25 wt % divinylbenzene as cross-linking agent, random copolymers poly(4-vinylpyridine-co-styrene) (P4VP-co-S) (10 and 50 wt % styrene), and block copolymer P4VP-b-S (50 wt % styrene). The temperature range was 55-70 degreesC. Sorption in P4VP-co-10%S copolymer is significantly higher than that in the respective homopolymers. Sorption in P4VP-co-50%S is close to that in linear P4VP, while the sorption curve (solvent activity vs solvent weight fraction) for P4VP-b-50%S lies in between those for the two parent homopolymers. For cross-linked P4VP, the amount of solvent absorbed by the polymers strongly depends on the weight fraction of the cross-linking agent. When solvent activity is plotted as a function of solvent weight fraction for various degrees of cross-linking, there is an unexpected crossover among the curves. At low solvent activity, the largest sorption was for the 25% cross-linked polymer and the lowest for the linear polymer; however, at high solvent activity the curves snitch position, and the linear poly(4-vinylpyridine) absorbs more than the cross-linked poly(4-vinylpyridine). This unusual behavior may be explained by "intramolecular repulsion" between bonded unlike segments (4-vinylpyridine and styrene/divinylbenzene in un-cross-linked/cross-linked copolymers, respectively) and by elastic contributions to the solvent chemical potential in cross-linked P4VP. In block copolymers, segregated sequence of the unlike monomers minimizes the effect of "intramolecular repulsion".