In this study, we investigate the alignment of colloidal CdSe/CdS core/shell NRs by probing the AC field-driven optical response. A statistical model based on a 3rd order von Mises-Fisher distribution 32 , i.e., a normal distribution describing 3-dimensional vector orientations, is used in conjunction with ensemble fluorescence anisotropy measurements to determine the average NR orientation relative to the direction of the applied field. We examine how varying the concentration of NRs impacts their electro-optic response and ensemble anisotropy to gain further insight into spontaneous mesoscale self-assembly.