Disclosed herein are compounds, compositions, methods, and kits for detecting reactive oxygen species (ROS) by conventional fluorescence microscopy, fluorescence spectroscopy, flow cytometry, and/or high content imaging. The compounds disclosed herein are novel reduced nucleic acid binding cyanine dyes, which dyes are probes for detecting ROS and measuring oxidative stress in cells either in vitro and/or in vivo. Also described herein are processes for preparing novel reduced dyes, i.e., ROS probes, for use in the disclosed compositions, methods and kits.