I've learned that
dies- can mean
jen- can also mean that.
jen- be used in preference to
The demonstrative pronouns dieser/diese/diese and jener/jene/jenes are used as demonstrative articles, as stand alone words or as a substitute for a noun.
There are also some derived adverbs:
The noun das Diesseits means our world/life, while das Jenseits means "afterlife."