Our studies on the synthesis and properties of dehydroannulenes containing acetylenic and cumulenic linkages in their cyclic systems (“acetylene-cumulene” dehydroannulenes) are briefly described. The “acetylene-cumulene” dehydroannulenes hold conformational stability owing to the presence of rigid and straight sp-sp hybridized linkages in the cyclic system, thus affording reliable information on the structure and the π-electron character of the annulene system.