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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.

2,5-Diarylarsoles were easily synthesized from nonvolatile arsenic precursors. Diiodoarsine was generated in situ and reacted with titanacyclopentadienes to give 2,5-diarylarsoles. The structures and optical properties were studied in comparison with those of 2,5-diarylphosphole. It was found that the arsoles were much more stable in the air than the phosphole. Single crystal X-ray diffraction revealed the arsenic atoms adopted a trigonal pyramidal structure, reflecting on the s-character of the lone pair. The obtained 2,5-diarylarsoles and 2,5-diarylphosphole showed intense emission in solutions and solid state. In addition, the optical properties were controlled by transition-metal coordination.