My friend will be paying $300,000 in taxes for the sale of his company this year. I am a teacher. Can he give this to my school for the equivalent tax credit?

[Bsch4477]

If he has already filed, he must pay whatever tax that he owes. There is no off-set available. If he has not filed, he can reduce what he owes by making a charitable contribution to your school if it is a tax exempt charitable institution. 

[Mike9241]

However, even if your school is tax-exempt and he gifts it his company. the cash he loses from not owning it when the sale is completed is going to be far more than the taxes he saves.

and he would need significant other income in the year of the gift to be able to fully deduct the value of the gift.

[SteamTrain]

Annnd....both of you need to remember that a charitable donation would not be a tax "Credit".....it would be an Income Deduction for the friend.  Which is not the same thing.   His reduction in taxes would be a certain lower % of his contribution, related to his tax bracket when he files.