The hyperpolarization of biomolecules at room temperature could facilitate highly sensitive magnetic resonance imaging for metabolic studies and nuclear magnetic resonance (NMR)-based screenings for drug discovery. In this study, we demonstrate the hyperpolarization of biomolecules in eutectic crystals using photoexcited triplet electrons at room temperature. Eutectic crystals composed of the domains of benzoic acid doped with the polarization source and analyte domains were prepared using a melting-quenching process. Spin diffusion between the benzoic acid and analyte domain was elucidated using solid-state NMR analysis, indicating that hyperpolarization was transferred from the domain of benzoic acid to the domain of the analyte.