Hi Im new here and I need help,

My boyfriend came here with a tourist visa and now it expired, were planning to get married but Im just a green card holder will this help him get a green card too or at least be a legal resident or do I have to be a US citizen to do that?

I am actually planning to apply for citizenship then get married with him so that I could help him with his papers which option is better?

I need help or guidance from you guys ASAP.