A possible molecular origin of the contorting water-solubility of butanol isomers lies in the self-association propensity of alcohols as well as on the specific interaction between the hydrophilic and hydrophobic moiety of butanol(s) with water. We have made a synergistic approach using far-IR (50–600 cm−1)-FTIR and MD simulation measurements to probe the extent of alteration of HBond structure of water-network in water-alcohol mixtures. The experimental and computational observations infer that extent of hydration of the non-polar moiety of the alcohol self-aggregates plays a decisive role in the (de)mixing of butanol(s) in water.