As shown in a, EM 12+ can accept two electrons from H2S, and converts into EM 2. The UV-Vis absorption of EM 12+ is
located above 500 nm, while upon reduction by H2S, it is located below 500 nm. A distinct color change from blue to light yellow is obseved. This color change can be applied for the development of H2S-activatable fluorescence imaging probes for in vivo imaging. We have published these results in 2018 (JACS, 2018, 140, 16340), with a great collaboration with Prof. Takanori Suzuki in Hokkodai Univeristy.