No matter how badly you want to remarry, getting married before your divorce is final constitutes bigamy. Bigamy is illegal in all 50 states. A marriage to an illegal immigrant still constitutes a legal marriage under U.S. law. Thus, you cannot slip past your state's bigamy regulations simply by marrying a non-citizen.
Although a marriage between a U.S. citizen or permanent resident and an illegal immigrant is a legal marriage, your marital status when the marriage took place can render the marriage invalid. If your divorce is not final, you are still legally married to your first spouse. Any marriage to another individual that takes place before the prior marriage is terminated as an invalid marriage. Your divorce is not final until a judge signs your divorce decree. Once this occurs, you are free to remarry.
State laws vary widely regarding the punishment for bigamy. Generally, a bigamist can face either fines or imprisonment for the offense. Both the individual whose prior marriage is still in effect and the new spouse are guilty of bigamy. Depending on your state's laws and the specific circumstances surrounding your marriage, you may be charged in either the state where the bigamous marriage took place or the state in which you and your new spouse reside.
U.S. Citizenship and Immigration Services (USCIS) gives U.S. citizens and permanent residents the right to apply for a green card for their immigrant spouses based on marriage. Obtaining legal permanent residency for an illegal immigrant spouse, on the other hand, is a more challenging process, and it would be best to consult with a lawyer experienced in immigration law. However, if you did not wait until your divorce is final before marrying the immigrant, you won't have the valid marriage required to adjust your spouse's immigration status to that of a legal permanent resident. USCIS will then have the right to remove your spouse from the country and bar her from entering the country again for a period of three to 10 years.