Diploblasty is a state of the blastula in which there are two essential germ layers: the ectoderm and endoderm. Diploblastic living beings are life forms which create from such a blastula and incorporate cnidaria and Ctenophora, earlier assembled together in the phylum Coelenterata, yet later comprehension of their disparities brought about their being put in discrete phyla.
To answer the above:
Diploblastic animals have ectoderm and an endoderm as well as radial symmetry.