The synthesis and electrochemical properties of novel oxygen-containing pi
-electron donors (3a,b and 4), in which only one outer sulfur atom of the D
HTTF (dihydrotetrathiafulvalene)-fused donors (1a,b and 2) is replaced by o
xygen atom, has been investigated to explore new organic metals. Among the
3a-based CT (charge-transfer) complexes and salts, the TCNQ (tetracyanoquin
odimethane) complex and the BF4 salt exhibited metallic conducting behavior
.