the band structures of [V 2 (Ant)] ∞ and [Cr 2 (Ant)] ∞ shown in Figs. 2(a) and 2(b). The [V 2 (Ant)] ∞ total DOS and the partial DOS of V 3 d are shown in Fig. 2(c). It is found that the 100% spin-polarized DOS around Fermi level mainly come from the V 3 d orbitals, with small contribution from the C 2 d . A gap of 0.76 eV and 1.25 eV for [V 2 (Ant)] ∞ and [Cr 2 (Ant)] ∞ respectively is observed in the spin majority channel. Thus, [V 2 (Ant)] ∞ and [Cr 2 (Ant)] ∞ may be good candidates for spintronic devices and information storage. Note that our relsults on [V 2 (Ant)] ∞ presented here agree well with former calculations.[16] In both [TM 2 (Ant)] ∞ and [TM(Bz)] ∞ , TMs are located in a crystal field with D$_{6}$$_{h}$ sym- metry. Under D$_{6}$$_{h}$ symmetry crystal field, as shown in Fig. 3(a), TMs d orbital splits into a a 1 (d 3 z $^{2$_{−}$}$r2 ), 2-fold e 2 (d$_{xy}$ and d$_{x}$ $^{2$_{−}$}$y2 ) and e 1 (d$_{xz}$ and d$_{yz}$) orbitals. In the mean- time, both Ant and Bz containing 14 and 6 C atoms obey the H¨ ukckel rule, which means that a stable aromatic molecule should have 4 m +2 carbon atoms (where m is an inte- ger). However, the magnetic behaviors of [TM 2 (Ant)] ∞ are totally different from those of [TM(Bz)] ∞ .[7] For example, [Mn(Bz)] ∞ is a ferromagnet with 1.0 µ B magnetic moment per Mn ions, and non-magnetic state is the ground state of [Cr(Bz)] ∞ . Whereas, this situation is reversed in [TM 2 (Ant)] ∞ , since [Mn 2 (Ant)] ∞ do not show any magnetic moment while Cr ions of [Cr 2 (Ant)] ∞ are ferromagnetically spin-polarized with 1 µ B magnetic moment. Both [V(Bz)] ∞ and [V 2 (Ant)] ∞ are a spin-polarized sandwich polymers, but the magnetic moments of V ions in [V(Bz)] ∞ and [V 2 (Ant)] ∞ are approximately 1.0 µ $_{B}$[7] and 2.0 µ $_{B}$, re- spectively. An interesting question arises from these results: Why is there so big difference in the magnetic properties of [TM 2 (Ant)] ∞ and [TM(Bz)] ∞ ? Further analysis shows that, compared with [TM(Bz)] ∞ , there is a larger CT between TMs and Ant. We find that the magnetic properties of [TM 2 (Ant)] ∞ are attributed to the CT effect which was once proved to be responsible for the magnetic behaviors of [TM(Cp)] ∞ .[12] For example, in [V(Bz)] ∞ , V (3d $^{3}$4s$^{2}$) has five valence electrons occupy the d orbitals with two and three electrons respectively occupying the a$_{1}$ and doubly degenerate e$_{2}$ orbitals, because of two s electrons fill 3 d shell[5]. Hence, one unpaired electron exists in e$_{2}$ orbitals, and [V(Bz)] ∞ shows a magnetic moment of 1.0 µ B on each V ion. However, in [V 2 (Ant)] ∞ , one electron at V d orbital is transferred to Ant, and e$_{2}$ has two unpaired electrons. Thus, V ions in [V 2 (Ant)] ∞ possess a 2.0 µ B magnetic moment. In order to illustrate this effect more clearly, calculations are performed, with the unit cell containing two TMs and one Ant and the initial magnetic coupling of two TMs arranged as ferromagnetic. For each [TM 2 (Ant)] ∞ , 4