A method of forming a chalcogenophene compound of formula (I) includes reacting a compound of formula (II) with a chalcogenide salt in presence of a proton source. Y is O, S, Se, Te or Po. R1 is hydrogen, deuterium, an aliphatic, heteroaromatic, or aromatic group, or a precursor of a leaving group Z whose conjugate acid (HZ) has pKa less than 30. R2 is hydrogen, deuterium, or an aliphatic, heteroaromatic, or aromatic group. R1 and R2 may be the same or different, and may joint together to form a saturated or unsaturated, heteroalicyclic or alicyclic ring. R3 is, for example, alkyl, aryl, heteroaryl, organosilyl, organotin, or organogermyl. R3′ is the same as R3 or is hydrogen. X is a precursor of a leaving group X whose conjugate acid (HX) has a pKa of less than 30.