The synthesis of sulfur- and selenium-capped polyalkynes with two to four triple bonds was achieved. As startingmaterials the bis(trimethylsilyl)-protected polyalkynes were used, which were treated with MeLi/LiBr. The reaction of the resulting lithium salts with thiocyanatomethane and selenium/methyl iodide afforded 2(n) and 3(n), respectively. Spectroscopic (PE and UV) and quantum chemical investigations