@msr19
If you are legally married, you must file as married regardless of the immigration status of your spouse, Or the availability of any credits or deductions. You can file as married filing separately, or married filing jointly, but you must file using a married status. Filing as single constitutes tax fraud, and the IRS does not observe a statute of limitations for fraudulent tax returns. In other words, they can reopen your prior return at any time for the rest of your life if they wanted to.
Also, your spouse is never a dependent for the other dependent credit or any other tax credit. Your spouse is your spouse, and if you file jointly, you will have an increased standard deduction compared to filing single or filing married filing separately.
It is true that there are certain other tax benefits that a spouse only qualifies for if you have a tax number or Social Security number when you file an on-time tax return. (I don’t have a list of those benefits right now, and I don’t know whether or not they would affect you.) filing an amended return one or two years later is certainly not a “on time“ tax return, and if any of those tax benefits apply to your spouse, they won’t be awarded.
However, that is not a reason to skip filing the amended return. You must file as married if you were legally married on December 31 of that tax year. Filing an amended joint return and applying for the ITIN may still reduce your tax and result in a refund, because you would benefit from the lower tax rates and higher standard deduction for joint filing compared with single.
