of N nuclei (we used three values, = , and 𝜂 15𝑁 10% 30% of 15 N-Py) and measured the dependence for two 100% different concentrations of the catalyst. We have set the [𝐶] total concentration of substrate (both N labelled and nonlabelled) equal to 190 mM in order to achieve sufficient signalto-noise ratio in cases where the SABRE signal was low, i.e. LIGHT-SABRE experiments with an N enrichment = 10% . 𝜂 15𝑁 One can see that the effect of