Poly[(methylsilylene)ethynylene] (1) and poly[2,5-thiophenediyl(methylsilylene)] (2) are prepared in good yields. Thermogravimetric analysis and differential scanning calorimetry indicate the Si-H group to increase the pyrolysis residue yields. Gelation was achieved from polymer 1 to get improved preceramic materials. (C) 1998 John Wiley & Sons, Inc.