New polyferrocenylsiloxanes (PFSXs) and polyferrocenylsilazanes (PFSZs) with linear or linear-cyclic structure were prepared. The ceramic yields of the polymers were estimated by thermogravimetric analysis (TGA) and bulk pyrolysis, which closely depend on molecular structures. Compared with that of their linear counterparts having comparable molecular weights, the ceramic yields of linear-cyclic PFSX and PFSZ were much higher. The pyrolysis process was investigated by lysis character is (TGA) highly depend on their molecular weights and structures, infrared spectra, and pyrolysis-gas chromatography-mass spectra (Py-GC-MS) analysis. The results indicated rather amount of ferrocene-based small molecules were formed during the pyrolysis of linear polymers in the range of 25-300 degrees C, whereas the existence of crosslinking or branched structure in the linear-cyclic polymers prohibited this transformation, and therefore, dramatically improved the ceramic yields. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 3384-3390, 2010