The tax filing status as married or single is determined as of the last day of the year. So, if the divorce remains pending as of December 31^st, the parties are still married for tax purposes. If the divorce is granted during the tax year, then the parties’ marital status is probably single as of December 31^st. Typically, parties cannot be forced to sign a joint tax return. In most circumstances, it is usually more advantageous for parties to file a joint return than to file separately. The advice of a good CPA to give each spouse independent advice makes sense.