Hyperpolarization by dissolution dynamic nuclear polarization (dDNP) has enabled promising applications in spectroscopy and imaging, but remains poorly widespread due to experimental complexity. Broad democratization of dDNP could be realized by remote preparation and distribution of hyperpolarized samples from dedicated facilities. Here we show the synthesis of hyperpolarizing polymers (HYPOPs) that can generate radical- and contaminant-free hyperpolarized samples within minutes with lifetimes exceeding hours in the solid state. HYPOPs feature tunable macroporous porosity, with porous volumes up to 80% and concentration of nitroxide radicals grafted in the bulk matrix up to 285 μmol g. Analytes can be efficiently impregnated as aqueous/alcoholic solutions and hyperpolarized up to P(C) = 25% within 8 min, through the combination of H spin diffusion and H → C cross polarization. Solutions of C-analytes of biological interest hyperpolarized in HYPOPs display a very long solid-state C relaxation times of 5.7 h at 3.8 K, thus prefiguring transportation over long distances.