Encapsulation of fluorescent dyes inside polymeric nanomaterials enabled preparation of bright nanoparticles for a large scale of applications such as sensing and bioimaging. However, high dye loading required to achieving high brightness generally leads to aggregation caused quenching (ACQ). To address this issue a number of methods were developed, notably using aggregation induced emission (AIE), which yielded ultrabright fluorescent nanomaterials. However, this method is more suitable for preparation of nanostructures where the core of dye aggregates is coated with a polymer shell, rather than dispersion of the dye in the polymer matrix. The use of bulky side groups could also improve the brightness of polymeric materials, although this approach requires dedicated multi-step synthesis of rather complex dyes. Previously, we proposed to use bulky counterions to prevent ACQ in polymer matrixes. This method enabled high dye loadings inside polymeric NPs, yielding NPs of exceptional brightness and light-harvesting properties. They were successfully applied for amplified detection of nucleic acids and oxygen as well as for long term cell tracking and in vivo imaging at the single particle level. More recently we showed that the counterion method could be applied to preparation of ultrabright electrospun nanofibers. However, preparation of nanorods based on these bright polymeric materials have not been explored to date.