In this work, we have investigated the transport properties of field-effect transistors (FETs) based on various kinds of fullerene (C60, C 70, and C84) and azafullerene (C59N) peapods without and with interacting with light. The encapsulation of various fullerenes and azafullerene inside single-walled carbon nanotubes (SWNTs) is characterized by TEM. Our results indicate that the electrical transport properties of pristine SWNTs are extremely sensitive to the encapsulation of various kinds of fullerenes or azafullerenes. In addition, the photoinduced transport characteristics of various peapods are systematically investigated, and our findings demonstrate that they exhibit complete different transport behaviors compared with those observed for empty SWNTs. In addition, the conductance of azafullerene peapods shows much higher photoresponse sensitivity than those observed in fullerenes peapods, suggesting a different photoinduced charge transfer mechanism.