A method for the preparation of a sample comprising highly polarized nuclear spins is proposed, comprising at least the following steps: a) provision of molecules with 1,2-dione structural units and/or molecules with 2,5-diene-1,4-dione structural units in the solid state; b) generation of radicals from these molecules by photo induced electron transfer by a first electromagnetic irradiation in the visible or ultraviolet frequency range in the solid state; c) dynamic nuclear polarization in the presence of a magnetic field in the solid state by applying a second electromagnetic irradiation with a frequency adapted to transfer spin polarization from the electrons to the nuclear spins leading to a highly polarized state thereof. Furthermore uses of correspondingly prepared samples for NMR, MRS and MRI experiments are proposed.