Organoboron compounds are described that upon exposure to light absorb light and isomerize and form a dark-colored isomer. The dark-colored isomer converts back to the colorless isomer upon removal of light, or exposure to oxygen or heat. Such compounds can be added into polymeric matrices such as films. These compounds are suitable for UV-blocking, UV-detecting, and for oxygen-sensing applications. Uses include UV-blocking windows, sunglasses, and as indicators in packaging such as food packaging.