Dimensional Developments was a research company.
When Moloch got out from prison, Adrian Veidt offered him a termporary job, presenting him a chance to atone himself from his past life. He worked in an enclosed office comparing and cross-checking the results from research teams testing a new energy source. He didn't know that Veidt introduced some errors himself to check if Moloch could detect them. Veidt had hid a radioactive source in his office in order to cause cancer to him.
Dimensional Deveopments apparently did all the research concerning teleportation, ultimately triggering the alien monster.