Article based on thesis and co authorship I graduated 8 months ago with 7 SCI article published. Recently, I submitted another article based on my thesis work. My supervisor, who actually has no supervisory role in my thesis except for providing a monthly stipend, wants me to add him as a co-author. He argues that he supported my research,  but in fact I paid him back more than he supported me, in the form of my work on various projects (totally different than my thesis topic).

During my PhD he never took an  interest in my PhD thesis, rather he always used me for his short term industry projects. In 4.5 years we didn’t have a single discussion/meeting on my PhD thesis.

Is him asking me to add him as an author morally correct? What if I refuse his request? Can my action be consider an unethical act?
If this is the case, what he is doing is not morally correct. You can refuse his request and thank him inside the acknowledgement part of your article for helping you. An author of an article should make some major contributions to the work, even if he is not writing any part of the article. Minor contributors should be mentioned in the acknowledgement section.