(9E,11E,13E,15E)-9,11,13,15-Octadecatetraenoic Acid Ethyl-d5 Ester is labelled (9E,11E,13E,15E)-9,11,13,15-Octadecatetraenoic Acid Ethyl Ester (O235450) which is the ethyl ester of (9E,11E,13E,15E)-9,11,13,15-Octadecatetraenoic Acid (O235490), a naturally occurring fluorescent probe for membrane properties. It is also allows for stereoselective preparation of conjugated polyenes. This compound can be synthesized by using D425545.