CaMPARI2 is a fluorescent Ca[2+] indicator that converts from green to red fluorescence in the presence of simultaneous elevated intracellular Ca[2+] and light exposure. CaMPARI2 was derived from the CaMPARI sensor by site-directed mutagenesis and has improved fluorescence brightness, faster kinetics of Ca[2+] unbinding and a lower photoconversion rate in low Ca[2+] conditions (FBrf0240460).