This work provides a simple but efficient way of constructing violet fluorescent helical nanofibers by the self-assembly of chiral π-π conjugated molecules, phenanthro[9,10-d]imidazole (PIM) derivatives. PIM derivatives are well-known functional molecules, but the construction of PIM into functional architectures has not been carried out to date. By introducing l- and d-aniline pendants into PIM derivatives, PIM-d-Ala and PIM-l-Ala are synthesized, which not only have the properties of aggregation induced circular dichroism (AICD) and circular polarized luminescence (CPL), but also have the capacity to self-assemble into helical fibers. They have important applications in the increasing demand for the miniatured optics and electronic devices.