Compounds containing at least one C—C triple bond within a chain of at least 3 ring systems which have positive dielectric anisotropy, the use thereof for high-frequency components, liquid-crystalline media containing these compounds, and high-frequency components, in particular antennae, especially for the gigahertz region, containing these media. The liquid-crystalline media serve, for example, for the phase shifting of microwaves for tuneable phased-array antennae.