A method of making silethynyl polymers having units of the general formula --(R.sub.2 SiC.tbd.C)-- wherein each R independently denotes a hydrogen atom, an alkyl, aryl or alkenyl group or a substituted alkyl, aryl or alkenyl group having up to 18 carbon atoms comprises adding a lithium salt of one or more diethynylsilanes of the general formula R.sub.2 Si(C.tbd.CH).sub.2 to one or more dihalosilanes of the general formula R.sub.2 SiX.sub.2 where X is a halogen atom and allowing the components to react. Copolymers with alternating units can be made. Linear polymers are made preferentially. Limiting the use of solvent increases the percentage of linear polymers produced.