Abstract: A method for preparing ceramic materials and/or precursors thereof from polysilanes of formula (I): ##STR1## in which: n.gtoreq.1, x+y=1, with:0.3.ltoreq..times..ltoreq.1 and,preferably, 0.5.ltoreq.x.ltoreq.0.8, 0.ltoreq.y.ltoreq.0.7.Pyrolytic efficiency and the quality of the final ceramics may be increased by pyrolysis carefully selected polysilanes (I) in the presence of a catalytic amount of at least one boron compound and optionally in the presence of at least one unsaturated cross-linking agent, preferably a vinyl cross-linking agent. This method is useful for preparing ceramic articles such as fibres, films, binders and matrices for use, inter alia, in electronics, electro-optics, semiconductor technology and aeronautics.