CPHATN-1a Color Change (IMAGE) Hokkaido University Caption The newly created CPHATN-1a shown in its original state with a yellow color (left). After being exposed to an acidic solution, the compound changed its color to dark red (center), reverting back to its original color after the solution dissipates (right). Credit Photo credit: Hisaki I. <em>et al</em>., Acid Responsive Hydrogen-Bonded Organic Frameworks, <em>Journal of the American Chemical Society</em>, January 7, 2019.) Usage Restrictions This image is copyrighted and can be used for reporting this press release if properly credited. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.