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The electronic and transport properties of a series of covalently functionalized graphene sheets m (FeBz) n -G (m , n = 1, 2) are calculated by density functional theory (DFT) and the nonequilibrium Green's function (NEGF) methods. All the studied systems are chemically stable due to the d – π interaction between Fe and graphene. Addition of (FeBz) n (n = 1, 2) introduces a half-metallic behavior: the up-spin state degradates into a semiconductor channel while the down-spin state behaves as a metallic channel. Particularly, two-fold anisotropy magnetism could be obtained, with the ferromagnetic ordering extending either parallel to the graphene plane originated from the Fe- d up-spin state or perpendicular due to the d -electron coupling along the Fe-Bz-Fe-Bz chain in the down-spin state. Because of the trapping effect, attaching (FeBz) n decreases the conductivity. Anisotropy inherited from graphene after functionalized with (FeBz) n (n = 1, 2): zigzag direction has higher conductivity than armchair direction. The number and alignment style of (FeBz) n (n = 1, 2), and the spin-polarized character, all have impacts on the transport property. Our findings provide useful guidelines for achieving graphene-based electronic and spintronic nanodevices by attaching other similar long multi-decker metal-arene systems. [Display omitted] • Electronic and transport properties of functionalized graphene m (FeBz) n -G (m , n = 1, 2) are calculated theoretically. • Addition of (FeBz) n (n = 1, 2) introduces half-metallic behavior. • Ferromagnetic ordering extends not only parallel to the graphene plane but perpendicular to it. • Conductivity is determined by anisotropy inherited from graphene, number and alignment of (FeBz) n , and spin polarization. [ABSTRACT FROM AUTHOR]