Dithieno[3,2-b:2',3'-d]arsoles have been synthesized via a safe and easy synthetic procedure, in which volatile arsenic intermediates are excluded. The obtained dithienoarsole derivatives were stable in the ambient atmosphere, unlike their phosphorus analogues, dithienophospholes. The Suzuki-Miyaura coupling reaction is applicable for structural modification and expansion of the π-conjugated system, and carried out the polymerization of the compounds. Dithienoarsoles showed an intense emission not only in solution but also in the solid state, and their molecular packing was analyzed by X-ray crystallography. The main-chain type dithienoarsole polymer formed a luminescent film. This work has demonstrated that dithienoarsole is a promising building block for luminescent materials.