The cell viability of 4T1 cells treated with different concentrations of A) TH nano shell for 24 h. B) free PpIX and P‐TH for 4 h and then lasered for 5 min. C) Free Dox and D‐TH for 24 h. D) Treated with different concentrations of PpIX + Dox, DP‐TH, and ODP‐TH for 12 h and following with 5 min irradiation. E) Flow cytometry analysis of 4T1 cells apoptosis incubated with DP‐TH and ODP‐TH for 12 h following with 5 min irradiation. CLSM images (F) and flow cytometry analysis (G) of JC‐1 for 4T1 cells incubated with DP‐TH and ODP‐TH for 4 h and then lasered for 10 min or not. Red is polymeric JC‐1, green is monomeric JC‐1. Flow cytometry analysis (H) and CLSM images of DCF fluorescence (I) for 4T1 cells incubated with PpIX, P‐TH and OP‐TH for 4 h, then lasered for 5 min or not. J) Fluorescence images of 4T1 cells incubated with PpIX + Dox, DP‐TH, and ODP‐TH for 4 h and then lasered for 5 min or not. Green is Calcein‐AM, red is propidium iodide (PI). Mean ± SD, n = 3, p‐value were indicated by ** (p < 0.01) and *** (p < 0.001).