FIG. 1: The top view of [TM 2 (Ant)] ∞ (a) and five initial magnetic structures used in our calcula- tions: (b) NN , (c) FF , (d) FA , (E) AF , (f) AA . Blue circles and arrows respectively represent the non-magnetic state and magnetic moment direction of TMs. Arrows marked by X and Y denote the magnetic interactions inside one layer and between nearest two layers, respectively. FIG. 2: Spin-resolved electronic band structures for (a) [V 2 (Ant)] ∞ and (b) [Cr 2 (Ant)] ∞ , respec- tively. (c) the total DOS and V 3 d partial DOS of [V 2 (Ant)] ∞ . FIG. 3: (a) the spliting of TMs d orbitals under the D$_{6}$$_{h}$ symmetry crystal field. (b) the calculated magnetic moments (per TM ions) of ferromagnetic [TM 2 (Ant)] ∞ unit cell. The TMs electrons configurations and magnetic moments predicted by CT-module are also shown in (b). (c) the total V 3 d and C 2 p partial DOS of [V(Bz)] ∞ . (d) the total V 3 d and C 2 p partial DOS of [V 2 (Ant)] ∞ . Schematic HOMO and LUMO positions of Bz, V and Ant are shown in the left, middle and right, respectively. The wider blue arrow means a larger CT between V and Ant. FIG. 4: (a) Side view of the relaxed Sc 4 V 4 Ant 5 cluster. (b)The schematic structure of branched sandwich clusters constructed by pentacene, benzene and TMs. 10