A cationic aggregation-induced emission photosensitizer (AIE-PS) MNNPyBB has been reported to have antibacterial effects against both Gram-positive and Gram-negative bacteria. The bacterial kill mechanism has been investigated and elucidated. In a methicillin-resistant Staphylococcus aureus subcutaneous infection model, wound closure has been achieved with normal re-epithelialization and preserved skin morphology.