He was not only a scoundrel, but also a cruel man

Most are coordinating correlatives.

They include:-

both ... and
either ... or
neither ... nor
not only ... but also

For example:-

He was not only a scoundrel, but also a cruel man.

We use either…or together when we want to link two positives:-

For example:-

Either the president or the vice-president will go to the conference. (The president will go to the conference, or the vice-president will go, not both of them though.)

We use neither…nor together when we want to link two negative ideas:-

For example:-

Neither the president nor the vice-president were able to solve the problem. (The president couldn't solve the probliem and the vice-president couldn't solve it either.)

Some are subordinating correlatives.