A main problem of common cancer chemotherapy is the occurrence of severe side effects caused by insufficient selectivity of the applied drugs. A possible concept to overcome this limitation is light-driven prodrug monotherapy. The synthesis as well as photochemical and biological evaluation of new photoactivatable prodrugs is described. Best results were obtained with prodrug (S,S)-7 a. The photochemical labile protecting groups in (S,S)-7 a can easily be removed by irradiation with UV-A light in 30 min with a power of only 2 J cm−2. The determination of the in vitro cytotoxicity by using an HTCFA-test reveals a QIC50 value of 8200 and the prodrug is more than two million times less cytotoxic than the corresponding seco-drug (−)-(S,S)-5 with an IC50 value of about 110 fM. The big therapeutic window makes (S,S)-7 a very suitable for its use in selective cancer therapy.