The sustainable separation of hydrocarbons from crude oil is critical for reducing energy consumption and carbon emissions in the chemical industry. Current methods are energy intensive and do not allow for isolation of specific hydrocarbons due to overlapping physicochemical properties and molecular complexities in crude oil. Here we introduce an energy-efficient molecular sieving strategy using cucurbit[7]uril (CB[7]) aqueous solution to directly extract cyclohexane (CH) from crude oil. CB[7] enables efficient CH separation under ambient and harsh conditions through shape- and size-selective binding with an ultrahigh affinity (2.5 × 109 M−1). Industrial validation shows >99% CH purity from azeotropic benzene mixtures and crude distillates and achieves 57.4–82.4% energy savings compared with current industrial methods. By demonstrating the scalability and robustness of CB[7]-based separations, this work highlights the potential of molecular sieves for sustainable, cost-effective hydrocarbon recovery from crude oil, paving the way for large-scale, sustainable hydrocarbon purification.