CLSM images of fixed HeLa cells stained by DAPI (blue) with DTIBT‐NCs (red, A) and rod‐like TIBT‐NRs (red, B). CLSM image of fixed HeLa cells stained by DAPI (blue) with spherical TIBT‐NCs (red, C), and CLSM image of these cells in (C) after 5 days of preservation (D). CLSM image of living HeLa cells stained by DTIBT‐NCs (E–I) and TIBT‐NCs (J–N) within 5 days. Fluorescence images of HeLa cells stained with DCFH‐DA and DTIBT‐NCs (O,R), TIBT‐NRs (P,S), or TIBT‐NCs (Q,T) treated in darkness (O–Q) and under light irradiation (400–800 nm, 10 mW cm⁻², 5 min; R–T). Cell viability of 4T1 cells treated by DTIBT‐NCs, TIBT‐NRs, or TIBT‐NCs in the presence and absence of white light irradiation (400–800 nm, 140 mW cm⁻², 5 min; U). Data are shown as mean ± SD (n = 5).