Is this legal in the state of Ohio?

There was a man that reported discrimination to his HR dept and also another supervisor that reported hearing discriminatory statements and after he reported this, the HR dept came and terminated this guy stating he was creating a hostile enviroment and 2 months later, they fired the supervisor that reported it too. Is this legal in ohio.

No you can't be fired for reporting someone harassing you or another person. The person doing the harassment should have been let go. That's a suit but hard to prove.