Ozone (O3) is ubiquitous in the environment and exposure to high levels of O3 has been associated with various respiratory diseases, such as asthma, emphysema, and bronchitis. Therefore, it is necessary to develop a simple and efficient detection method for monitoring O3 in the environment and living cells. In this study, an intramolecular charge-transfer (ICT) compound was designed and synthesized based on a phenol-type hemicyanine dye and 4-bromo-1-butene, which could specifically detect O3 in aqueous solution. Due to the ICT process, the absorption spectrum, fluorescence spectrum, and color of the probe hemicyanine-butyl-3-enyl (HCB) changed significantly and thus the rapid and sensitive detection of O3 was realized. The interaction between O3 and the probe HCB could be completed within 40 min, and the detection limit of O3 was as low as 2.15 × 10-7 mol L-1. Finally, the proposed method was successfully applied to the visual detection of O3 in a simulated O3 environment and living cells.