Polyphenylcarbosilane as a novel preceramic polymer for SiC was synthesized by thermal rearrangement of polymethylphenylsilane at around 350-430 A degrees C. Characterization of the synthesized polyphenylcarbosilane was performed using Si-29 NMR, C-13 NMR and H-1 NMR spectroscopy, FT-IR spectroscopy and TG, XRD, and GPC analysis. From the FT-IR data, the band at 1035 cm(-1) was very strong and was assigned to the CH2 bending vibration in the Si-CH2-Si group, indicating the formation of polyphenylcarbosilane. The average molecular weight (M-w) of the polyphenylcarbosilane synthesized was 2,500, and it was found to easily dissolve in an organic solvent. TGA data indicate that polyphenylcarbosilane is thermally stable up to 200 A degrees C. However, rapid weight loss occurs above 200 A degrees C because of the decomposition of polyphenylcarbosilane, and the diffraction peak of the pyrolysis residue at 1200 A degrees C corresponds to beta-SiC ceramic. The ceramic yield calculated from TGA is approximately 60%.