The high strength of silicon–halogen bonds can be leveraged toward the synthesis of phosphaalkynes. Heating bis-trimethylsilylated methyldichlorophosphines ((SiMe)CRPCl) under vacuum results in the expulsion of two equivalents of chlorotrimethylsilane and the ultimate formation of a new phosphaalkyne. This synthetic strategy has been applied in the synthesis of 2-phenylphosphaacetylene and 2-trimethylsilylphosphaacetylene. As in the case of synthetic routes reliant upon the elimination of a hydrogen halide, this route is suspected to involve an intermediate phosphaethylene species containing a C=P double bond, though such a species has not yet been observed.