To provide a method for producing the subject compound, capable of providing a cured product having fast curing rate excellent in heat resistance and electric characteristics and useful as a resin for semiconductor sealing, resin, etc., for laminated plates by constituting the compound so as to have a specific structure.

This new compound has a structure represented by formula I [R1 to R8 are each H or 1-6C alkyl; (n) is 0-10; Z1 and Z2 are each S or O and either one of R1 to R8 is S]. The compound of formula I can be obtained by reacting, e.g. (A) an epoxy compound of formula II with (B) a sulfiding agent in an amount of 0.05-5 mol, preferably 1-5 mol based on 1 equivalent epoxy group of the component A in the presence of a solvent at -15 to 100°C, preferably 0-50°C for 0.5-30 hr. Thiocyanic acid salts, thioureas, etc., is preferable as the component B. The thermosetting resin is obtained by including preferably 5-95 wt.% of the compound with an epoxy compound.