Figure shows the dependence of the magnetization (Iz) on the magnetic field, and Figure shows the field dependence of the singlet order of azobenzene, measured on 15 N nuclei. In Figure , we compared the field profiles on 15 N, 1 H and 13 C nuclei. It is important to note, that we measured C polarization with natural isotopic abundance. Polarized protons are detected on molecules with 12 C nuclei. In this paper, we do not discuss field dependence in detail; it was measured only to find the optimal magnetic field for different types of nuclei (200 nT for 1 H, and 400 nT for the 15 N and 13 C nuclei).