Theyres only so many elements and so many ways to mix them to create new stuff, thats why most "new" chemicals are just different mixes of "old" stuff.

So until we setup a moon colony and start mining meteors and astroids, I wouldnt start holding my breath for anything truly "new"

On the other hand, Im sure the Government has plenty of Agent Orange left over in a warehouse somewhere. It doesnt satisify your "new" requirement, and crop burn is a slight concern, but man will it smoke marestail and waterhemp lol