One-dimensional quantum rods (QRs) have the properties of the electron and hole are separated under the electric field, the overlap of the wave function decreases, and photoluminescence quenching occurs. Because of these properties, QRs can be used in optical switching and future display applications. The CdZnS/ZnS QR is a material capable of emitting blue light. CdZnS/ZnS can easily separate carriers because the difference between the valence band of the core and the shell is small. However, CdS and ZnS have very low hole conductivity and cannot easily be separated. To solve this problem, we developed an in situ doping system and demonstrated nitrogen doping. The in situ doping system not only coats ZnS onto CdZnS QR but also proceeds with nitrogen doping. Previously studied doping methods additionally doped the synthesized nanomaterials and had no effect of doping because the dopant was not dispersed without subsequent heat treatment. However, the in situ doping system grows the ZnS shell and uniformly dopes the nitrogen. This means that no additional heat treatment is required. The effect of doping gradually increases in proportion to the amount of dopant and the PL quenching increases, even though the aspect ratio is decreased.