Development of dual-responsive fluorescent molecules for monitoring both environmentally and biologically concerned metal ions is a burgeoning area of research and are of paramount importance. In light of this, a new phenothiazine-based ICT fluorescent probe PDABOH is developed with both -NH and -OH groups, making it an ideal receptor for Cu2+ and Fe3+ ions. The photophysical characterizations revealed that when Cu2+ and Fe3+ ions are present, the strong fluorescence of PDABOH apparently quenched along with the formation of new emission band. PDABOH forms chelation complexes with Cu2+ and Fe3+ leading to fluorescence quenching upon interaction and the mechanism of quenching has been validated by EPR spectral analysis. Intriguingly, PDABOH exhibited excellent performance including high specificity, sensitivity in nanomolar levels, solid anti-interference and prompt response towards Cu2+ and Fe3+ ions. Quantitative analysis of PDABOH in water samples demonstrated a great potential for use in physiological media. On the other hand, counting the good fluorescence quantum efficiency and low cytotoxicity validated by MTT assay, it was successfully employed for imaging live cells. Notably, PDABOH offered significant cellular internalization with higher uptake by MCF-7 cells highlighting its promise for biological and environmental applicability. © 2025 Elsevier B.V.