A novel pi-extended tetrathiafulvalene (exTTF) analogue having a dihydro-s-indacene core has been synthesized as a new class of donor-acceptor (D-A) system. X-ray analysis reveals a deformed structure of the 1,3-dithiole rings from the central core due to the steric repulsion, leading a mesomeric betaine structure for resonance. While a solution of the exTTF displays solvatochromism, its crystal provides metallic luster color. The exTTF undergoes both oxidation and reduction easily in electrochemical measurements.