The addition of L-cysteine without blocking amino and carboxyl groups to${eta},{eta}$-dinitrostyrene derivatives(11a-e) were investigated. ${eta},{eta}$ -Dinitrostyrene derivatives(11a-e) easily undergo addition reactions with L-cysteine to from s-(2,2-dinitro-1-phenylethyl)-L-cysteine(12a), s-[2,2-dinitro-1-(p-methyl)phenylethyl]-L-cysteine (12b), s-[2,2-dinitro-1-(p-methoxy)phenylethyl]-L-cystein e(12c), s-[2,2-dinitro-1-(p-chloro)phenylethyl]-L-cysteine (12d) and s-[2,2-dinitro-1-(p-nitro)phenylethyl]-L-cysteine( 12a), respectively. The structure of adducts were confirmed by means of spectral data, molecular weight measurement and elemental analysis.