Abstract The effective capture of volatile organic compounds (VOCs) and very volatile organic compounds (VVOCs) is crucial for controlling indoor air quality, environmental monitoring, and emission regulation. However, effective VVOC adsorption remains challenging due to their low boiling points, high vapour pressures, and the susceptibility of many adsorbents to competitive water sorption. Here, we report a systematic study on the role of chemical functionality in hypercrosslinked polymers for (V)VOC capture under realistic operational conditions. A series of fluorene‐based hypercrosslinked polymers bearing heteroatom substituents (C, N, O, S, and SO 2 ) was synthesised and characterised, exhibiting high thermal stability, surface areas up to 1600 m 2 ·g −1 , and micro‐/mesoporous architectures. The adsorption performance of these networks is evaluated using thermodesorption‐ and headspace‐gas chromatography–mass spectrometry. Under both dry and humid atmospheres, the hypercrosslinked polymers outperform a commercial benchmark sorbent in the uptake of a ten‐component (V)VOC mixture, with the amine‐functionalised network achieving the broadest analyte retention range even in the presence of water vapour. Our findings elucidate how polymer chemistry governs sorption behaviour and establish hypercrosslinked polymers as high‐performance, tuneable alternatives to state‐of‐the‐art commercial sorbents for capturing volatile analytes.