This proposal aims to investigate the effect of magnetic impurities on the ALC resonance amplitude of an organic semiconductor (RRa-P3HT), to determine whether the effect can be quantified. Previous measurements have found that for a small concentration of magnetic impurities (0.004%), a 10% increase in the ALC amplitude occurs at 300K. In this experiment, we propose to systematically change the magnetic impurity concentration in the RRa-P3HT, from 0.001% to 0.02% to determine how the ALC amplitude changes. The ALC resonances will also be model to allow for further understanding and quantification of the different processes contributing to the overall magnitude.