A low dielectric constant polymer, comprising monomeric units derived from a compound having the general formula I (R.sup.1--R.sup.2).sub.n--Si--(X.sup.1).sub.4-n, wherein each X.sup.1 is independently selected from hydrogen and inorganic leaving groups, R.sup.2 is an optional group and comprises an alkylene having 1 to 6 carbon atoms or an arylene, R.sup.1 is a polycycloalkyl group and n is an integer 1 to 3. The polymer has excellent electrical and mechanical properties.