A series of carborane derivatives (o-CB-DPE, E = O, S, Se) were synthesized through a combining of the σ characteristic o-carborane and chalcogen-fused phenazines. The UV-Vis spectroscopy and cyclic voltammetry results showed that o-CB-DPEs have a visible light absorption (λ > 390 nm), narrow energy gap (∼2.93 eV), and stable radical cation species. The radical cation formation process of these was proved by spectroelectrochemistry and chemical oxidation with AgSbF6. Based on the above advantages, o-CB-DPS showed an excellent performance on ATRP (Đ = 1.12, C(MMA) = 97%) due to the long radical cation lifetime (700 s). These results prove that combining carborane and chalcogen-fused phenazine is a feasible method to improve the efficiency of metal-free photocatalytic ATRP.