In AFM ground state, the band gap opens, indicating the semi-conducting nature with spin-degenerate levels and zero net magnetic moment. In marked contrast to this, FM state results in breaking of spin degeneracy, as implied by both band structure and DOS plot. The spin up and spin down bands cross in non-bonding fashion, indicating metallic behaviour with net magnetic moment of 0.58 µ B . Notably, no significant difference is observed in the bulk bands of NM, AFM and FM cases, implying that magnetic effects on the bulk bands are negligible. The non-zero magnetic moment and breaking of spin-degeneracy in FM state prompted us to investigate the transport characteristics of ZGNRH in FM state along with the ground AFM ZGNRH and NM AGNRH case. Furthermore, we also intended to authenticate whether GNR retains its AFM/FM or NM ground state upon decreasing the width of scattering region from infinitely long GNR to a molecular chain so as to tune the spin-polarization effects.