As electronic devices continued to shrink in size, there is a need for innovative materials that can overcome the limitations of traditional silicon based. This research presents a simulation based comparative study of Graphene Field Effect Transistors (GFETs) and Carbon Nanotube Field Effect Transistors (CNTFETs) to evaluate their performance for future electronics devices and applications. The research focuses on analyzing I-V characteristics and temperature dependence across a series of 300 K to 600 K. Simulation results show that Graphene Field Effect Transistors (GFETs) exhibit direct conduction and exceptional thermal stability but suffer from poor switching performance due to the absence of a bandgap, while Carbon Nanotube Field Effect Transistors (CNTFETs) demonstrate strong gate control, high on/off ratios, and digital switching capabilities. The Ion/Ioff ratio for Carbon Nanotube Field Effect Transistors (CNTFETs) decreases dramatically from 4.544×10⁵ at 300 K to 945.9 at 600 K. These results suggest that Graphene Field Effect Transistors (GFETs) are better suitable for analog and Radio Frequency (RF) applications, while Carbon Nanotube Field Effect Transistors (CNTFETs) are ideal for digital logic at ambient conditions. The study recommends the investigation of hybrid architectures and thermal optimization for strong Nano electronic device performance.