Conversation so far:
when was dc comics bought by warner brothers?
In March 1989, Warner Communications merged with Time Inc., making DC Comics a subsidiary of Time Warner.
what was the first DC Comics film after the Warner Communications, Time Inc. merger in March 1989?
In June, the first Tim Burton directed Batman movie was released

Question: what were the first materials published?
Self-contained rewrite: what were the first materials published by DC Comics after the Warner Communiations, Time Inc. merger in March 1989?