A series of new crown‐ether annelated TTF derivatives 2a, 2b, 2c, 3 and 5 have been synthesized and characterized by melting points, NMR, IR and ESI‐MS. The crystal structure of compound 3 , 2, 3‐dithia‐(5′,8′‐dioxaoctyl)‐6,7‐ethylenedithiatetrathiafulvalene, has been determined by X‐ray crystallography. Redox properties of all these compounds have been investigated by cyclic voltammetry and each compound shows two reversible single‐electron redox couples. The results indicate that 3 is responsive for Li+, but not to other alkali metal cations, such as Na+ and K+. Although with the same cavity, compounds 2c and 5 show marked changes upon the addition of sodium perchlorate, while there is no significant response for 2a and 2b at the same condition.
