To obtain a monoazo compound which is an aliphatic vinyl sulfone- based reactive dye, good in exhaustion characteristics and fixing ratio, having excellent buildup properties and a high color value and capable of providing a yellow dyed and printed materials good in bonding stability of fiber-dye.
This monoazo compound is represented by formula I [X is Cl, F, etc.; Z1 is vinyl, CH2CH2OSO3H, etc.; (n) is 2 or 3; (m) is an integer of 2-6], e.g. a monoazo compound represented by formula II. The compound represented by formula I is obtained by condensing a monoazo intermediate compound represented by formula III and a compound represented by the formula H2N(CH2)mSO2Z1 with 2,4,6-trichloro-s-triazine, etc.