Whenever I see a reference to "Hegel's dialectic of thesis, antithesis and synthesis", I wonder where people are getting it. They're obviously not reading it in Hegel himself. You can find it in some of the older books about Hegel, and you can find it in Marx, but if we go way back to the late 1700s, we can see what may be its earliest appearance in Fichte:
This may not even be Fichte's oldest reference, but it comes from his Science of Knowledge, 1794 (Grundlage der gesammten Wissenschaftslehre) (translated by Heath & Lachs).
Maybe you could say Hegel got it from Fichte ... except that Hegel never says this!
The only place I know of where Hegel specifically mentions "T - A - S" is in the History of Philosophy (just before getting to Fichte) where he's talking about Kant:
This is the old Haldane & Simson (no p) translation, vol. 3, p. 477.
If you read the whole paragraph, you see Hegel is quite critical of this "triplicity".