PURPOSE:To provide a new 2,3-dihydro-4H-1-benzopyran-4-one derivative useful as an intermediate for a 4H-1-benzopyran-4-one derivative having excellent anti-inflammatory action, antipyretic analgesic action, antiarthritic action and antiallergic action. CONSTITUTION:This benzopyranone derivative is expressed by formula I [R1 is a (halogen-substituted)lower alkyl, a lower alkenyl or an aryl; R is H, an alkyl or an acyl; R is H, a halogen, cyano, a (substituted)alkyl, etc.; R is H, a halogen, NO2, cyano, carboxyl, etc.; R is a (substituted)phenyl, thionyl, a furyl, etc.; Z is O, S or imino] or its salt, e.g. 2,3-dihydro-7- methylsulfonylamino-6-phenoxy-4H-1-benzopyran-4-one. The compound of formula I is produced by cyclizing a compound of formula II (R is R ; R is R ) with a condensing agent such as phosphorus pentoxide.