What would be the jurisdictional code?

To file a complaint based on Sexual harassment in Illinois you first have to file a complaint with either the Illinois Department of Human Rights ("IDHR") or Equal Employment Opportunity Commission ("EEOC")--if you file with the IDHR they will automatically cross-file with the EEOC. You can't file directly with the state or federal courts. Once you file you can ask for a "right to sue letter" from the EEOC or wait for the IDHR investigation and then file a lawsuit in the local circuit court.

Diversity Jurisdiction is for a lawsuit based in federal court only. Usually, in order for diversity jurisdiction to apply, none of the plaintiffs in a case can be from the same state as any of the defendants (complete diversity). A corporation is treated as a citizen of the state in which it is incorporated and the state in which its principal place of business is located, though a partnership or limited liability company is considered to have the citizenship of all of its constituent partners/members. Thus, a partnership with one partner sharing citizenship with an opposing party will destroy diversity of jurisdiction

It is unclear if you are trying to file in state or federal court.