9-(4-Dimethylamino-phenyl)-3,7-dimethyl-nona-2,4,6,8-tetraenenitrile

References:
Azimi Hashemi N, Erbguth K, Vogt A, Riemensperger T, Rauch E, Woodmansee D, Nagpal J, Brauner M, Sheves M, Fiala A, Kattner L, Trauner D, Hegemann P, Gottschalk A, Liewald JF:
Synthetic retinal analogues modify the spectral and kinetic characteristics of microbial rhodopsin optogenetic tools. Nature Communications (5):1-12, 2014