Spintronics is one of the new areas being promoted as a potential replacement for next-generation electronic systems. It utilizes both the charge and spin degrees of freedom of electrons to transfer, process, and store information. Spintronics provides devices with faster data processing, more data storage, increased circuit integration density, and lower power consumption as compared to conventional electronic devices. Despite the tremendous potential of spintronics devices, there are several issues in order to obtain high-performance devices, such as the generation and injection of spin-polarized carriers, spin-polarized transportation over large distances, manipulation, and detection of spin carriers. Different materials, such as transition metals, topological insulators, diluted and intrinsic magnetic semiconductors, carbon-based nanomaterials, transition metal dichalcogenides, organic molecular junctions, etc., having different electronic and magnetic properties have been proposed in this regard. Since the spin-dependent chemical potential exponentially decays during spin diffusion due to spin relaxation. Thus, a spin channel with a long spin lifetime and a long spin diffusion length is needed. Graphene is considered, a very promising candidate for long-distance spin transport due to its weak spin-orbit coupling, long spin coherence length, high electrical mobility, and gate-tunable carrier concentration. For example, Kamalakar et al. have demonstrated spin transport in a graphene channel over a channel length of 16 µm with a spin lifetime of 1.2 ns and 6 µm diffusion length at room temperature. However, the zero band gap non-magnetic semi-metal nature of pure graphene restricts its use in spintronics. Therefore, changes to graphene's electrical and magnetic characteristics are needed in order to utilize it in spintronics device applications. In graphene, significant progress has been made in achieving a suitable band gap. One of the effective methods for widening the band gap of graphene is the creation of 1D graphene nanoribbons (GNRs) from 2D graphene sheets. GNRs with different shapes and widths can be experimentally synthesized using lithography and bottom-up chemical synthesis using molecular precursors. The Band gap engineering and magnetic properties of GNRs have been extensively studied. The zig-zag graphene nanoribbons (ZGNRs) are low-bandgap magnetic semiconductors with antiferromagnetic coupling between the opposite edges. Recently, Xu et al. have experimentally demonstrated the edge-induced Kondo resonance in nonplanar zig-zag edge termini on bare Au(111). The antiferromagnetic coupling and spin-degenerate energy levels result in the poor magnetic moment of ZGNR, which limits its application in spintronics. Son et al. showed that an external in-plane electric field can break the spin degeneracy of ZGNRs resulting in half-metallic ZGNRs. Jaiswal et al. reported that fluorine passivation at zig-zag edges can induce half-metallicity in ZGNRs. Afterward, various schemes have been proposed in order to modulate ZGNR's magnetic properties for different device applications, such as chemical functionalizations and substitutions, and exploiting quantum interference (QI) effects to control spin-polarized electron transmission. Saraiva-Souza et al. reported the observation of destructive quantum interference (DQI) features in the electron transmission spectrum, by adding an imidazole donor group to the polyacetylene chain connected with the ZGNR electrodes. The observed DQI features can be further controlled by the application of gate voltage. Valli et al. have demonstrated that edge magnetism and QI can result in spinpolarized QI antiresonances in graphene nanoflakes with zigzag edges. Adsorption of the magnetic molecule on the surface of ZGNRs is another strategy to break the spin-degeneracy of ZGNRs. Hou et al. observed that the gapped ferromagnetic (FM) ZGNRs can be obtained by edge functionalization with a magnetic molecule. Cho et al. reported that ZGNRs can have a ferromagnetic ground state when both edges of ZGNRs are functionalized with different radicals. Nam et al. demonstrated that doping with B or N on the spin-coupling pathway of radical edge functionalized ZGNR can tune the magnetic edge coupling of the system from AFM to FM and vice-versa. Although, it was shown that edge functionalization of ZGNRs with radicals can break its spin-degeneracy and result in a FM state. A proper understanding of the effect of radical adsorption in the middle of ZGNRs on its electronic and quantum transport properties is required.