Thermochromism of rapid responses to temperature changes versus mechanochromism in a Ni-dithiolene complex salt.A thermochromic or mechanochromic material can switch between at least two stable states in response to changes in temperature or static pressure/strain.  Upon heating, 1 undergoes a reversible phase transition at around 340/320 K during the first heating/cooling cycle, resulting in rapid thermochromism with a color change from green (stable state) to red (metastable state) within a few seconds. 
THERM