MQA-P is a multifunctional near-infrared (NIR) fluorescent probe that simultaneously detects ONOO^–, viscosity, and polarity within mitochondria. MQA-P exhibits significant response to ONOO^–, λ_em=645 nm; and NIR channel at λ_em>704 nm Medium is highly sensitive to viscosity/polarity. MQA-P possesses excited-state intramolecular charge transfer (ESICT) properties that are highly sensitive to polarity by designing the N,N-dimethylamino group as the electron donor and the quinoline cation unit as the electron acceptor. MQA-P is used for ferroptosis or cancer diagnosis in vitro and in vivo via dual-channel images^[1][2].