Married couple filing jointly sell a one acre vacant tract of land which is immediately adjacent to and used as part of the primary residence for 100,000 on 08/24/2020.   Married couple then sell their primary residence itsself and all remaining acreage in March 2021.   IRS publication 523 makes it clear that this initial vacant land sale, and the later sale of the residence cannot be treated as one sale of the primary residence and apply the home sale gain exclusion rules.   My question is how to actually report this when these sale events occurred in two different tax years. 

I found conflicting things online.  One says that you should report the sale of the vacant land (which occurred first) as a capital gain event, pay the tax, and then in the next year when the home sells, go back and amend the prior years return and get a refund.   I found something different which says if the primary residence sells before the tax filing due date for the year that the vacant land sold then you do not have to report the sale of the vacant land in the year it happened.   Thoughts.