BackgroundDetecting diethyl chlorophosphate (DCP), a highly toxic chemical simulant for nerve agents like Sarin, Soman, and Tabun, is crucial due to its prevalence in warfare scenarios, as well as its presence in contaminated soil and air. Traditional detection methods often struggle with sensitivity and versatility, limiting their effectiveness in real-time, on-the-spot applications. Effective detection is vital for safety, environmental monitoring, and mitigating the risks associated with these hazardous substances. There is a pressing need for advanced sensors that can offer high sensitivity, specificity, and practicality in various environments. ResultsIn our study, we developed and introduced two ICT-based fluorocolorimetric sensors, TPAHY and TPAPD, designed for the detection of DCP. These sensors exhibit remarkable sensitivity, with limits of detection (LOD) at 23.31 nM for TPAHY and 28.42 nM for TPAPD. TPAHY proves to be an efficient sensor for the on-spot DCP detection, showcasing practical applications such as fluorescent sprays, pens, and detection devices. Upon addition of DCP, TPAHY undergoes a distinct colorimetric shift from yellow to orange, coupled with an enhancement of orange fluorescence. Conversely, TPAPD demonstrates a colorimetric transition from colourless to yellow and experiences fluorescence quenching from blue emission. To understand the underlying mechanisms, we conducted studies using density functional theory (DFT) and lifetime measurements, providing deeper insights into the sensor behaviours. SignificanceThe development of TPAHY and TPAPD provides reliable, sensitive, and versatile solutions for monitoring DCP. TPAHY not only serves as a useful tool for detecting DCP in various field applications but also extends its utility to biological imaging, as demonstrated in HeLa cell studies. This dual functionality enhances its relevance for both environmental monitoring and broader scientific investigations. These sensors represent a significant advancement in the detection of toxic chemicals, offering improved safety and research capabilities.