What’s the difference between “either…or” and “neither…

nor” ?

either…or

showing two alternatives / choices

only one of the two is valid

Examples

I am expecting you to come either today or tomorrow.

The employees either resigned or were dismissed.

neither…nor

linking two people / things / actions in a negative statement

both the two are not valid

Examples

I am expecting you to come neither today nor tomorrow.

I am expecting you to come either today or tomorrow.

The employees either resigned or were dismissed.

The employees neither resigned nor were dismissed.

Point to note

“neither…nor” + “not”

That was not the choice of neither Mary nor Susan.

That was the choice of neither Mary nor Susan.

That was not the choice of either Mary or Susan.