The degradation of chemical warfare agents O-ethyl S-[(2-diisopropylamino)ethyl] methylphosphonothioate (compound VX), bis(2-chloroethyl) sulfide (yperite) and their simulants diethyl 2-[(dimethoxyphosphorothioyl)sulfanyl]butanedioate (malathion) and diisopentyl sulfide were evaluated using singlet oxygen generated by irradiation of zinc phthalocyanine sulfonamide bearing oleyl group. The assessment was performed in three solvents using dissolved phthalocyanine and phthalocyanine embedded in an ethylene–vinyl acetate polymer matrix. Singlet oxygen production of tested phthalocyanine was estimated in solutions of methanol, toluene, dichloromethane and after its embedding into polymer. Similar values of singlet oxygen production were found in all solvents and in polymer it increases with increasing amount of phthalocyanine in the matrix. Decontamination of real contaminated sample was also verified. The degradation rates differ considerably and the roles of the solvents and the compound type are briefly discussed.