Silicon carbide (SiC) has attracted interest for environmental and energy applications due to its high temperature properties. Future industrial challenges for SiC, particularly in aeronautics, require to tune the materials composition and shape on demand. These inherent difficulties can be overcome by synthetic paths where molecular chemistry and chemistry of materials are combined, like the Polymer-Derived Ceramics route. The chemistry, processing properties and reactivity (thermal and chemical) of related polymers can be controlled and tailored to supply, after shaping and pyrolysis processes, ceramics with the desired compositional phase distribution and homogeneity. This method is used to prepare boron-modified SiC. Polymers were synthesized by the reaction of allylhydridopolycarbosilane (AHPCS) with borane dimethylsulfide. We demonstrate that the boron content has an effect on the chemistry and processability of precursors, as well as the properties of the resulting materials. This study gives us informations about the chemical and physical properties of boron-modified SiC precursors based on infrared, NMR spectroscopies and elemental analyses. Their pyrolysis behavior is investigated by solid-state NMR coupled with TGA. Final materials are characterized by XRD, elementary analysis, Raman spectroscopy. Applications of PDC route to process ceramic matrix composite will be discussed.