A compound represented by the following formula 1: wherein R1 is an unsubstituted or substituted benzyl group or unsubstituted or substituted phenyl group, method for producing a copolymer comprising copolymerizing a monomer mixture containing the compound, copolymer for lenses containing a copolymerized component represented by the following formula 2 and a lens consisting of the copolymer. The compound of the formula 1 is a reactive dye exhibiting excellent hydrolysis resistance, good copolymerizability with other comonomers, excellent dyeing property and proper solubility in comonomers.