VanNieuwenhze, Brun and co-workers have demonstrated that derivatives of D-amino acids (e.g., Dalanine) but not L-amino acids can be recognized by the metabolic cell wall machinery of bacterial cells and incorporated into their peptidoglycan cell walls (Figure ). Therefore, we prepared benzoselenadiazole derivatives of D-and L-alanine to examine whether the stereospecific incorporation of the D-enantiomer would be retained after conjugation to the photosensitizer. Two amino acids (12, the L-alanine surrogate and 13, the D-alanine surrogate, Figure ) were synthesized by nucleophilic substitution of the fluorinated benzoselenadiazole 4F with the two enantiomers of 2,3diaminopropionic acid ((Dapa), Figure , full synthetic details in Supplemental Information). Both amino acids exhibited similar optical properties and singlet oxygen quantum yields, indicating comparable phototoxicity potential (Table ).