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B 4 C ceramic is one of widely used ceramics with properties of low density, high hardness, high thermal-stability and high neutron absorption cross-section. However, the high melting point and high hardness of B 4 C make it difficult to be prepared as materials with complex shape. Precursor derived method is an effective approach to prepare special-shaped ceramics. In the early research of B 4 C ceramic precursors, highly toxic and unstable decaborane was generally used as the boron source material, and precursors were also unstable and difficult to synthesize. In this work, a new B 4 C precursor is designed and synthesized, and m-carborane, which has stable chemical properties and high thermal stability, is used as the boron source. Firstly, m-carborane is converted into lithium salt after removing active hydrogen by n-butyllithium. Then, catalyzed by Cu(I), the lithium salt reacts with m-chloroiodobenzene so that monomer, bis(3-chlorophenyl)-m-carborane, is prepared. The monomer is polymerized through Ullmann Coupling reaction at the present of Ni(0) catalyst and Zinc powder, and precursor poly[bis(3-chlorophenyl)-m-carborane] is finally synthesized. The precursor is stable at room temperature in air and soluble in Tetrahydrofuran, with Mw of 1013g/mol, and ceramic yield of 62.20% at 900°C in N 2 . The precursor pyrolytic product is composed of B 4 C and graphite after heat treated at 1600°C in inert atmosphere.

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