Birmingham Coroner's Court heard Ian Connell "walked into" a makeshift noose at his home after telling his partner: "I've got something to show you."
He died almost immediately.
The academic felt he had been "left high and dry" after losing his position at Wolverhampton University, his long-term partner said.
Suzanne Orsler told how Dr Connell, 49, hanged himself with a wooden- handled skipping rope at their home in Kings Heath, Birmingham, in June, seven weeks after losing his job. Fighting back tears, Ms Orsler, 36, told how she had followed her partner to his office in their attic.
She said: "I was just a couple of steps behind him. I didn't really realise what was happening. He looked really strange and then I saw something around his neck."
She said the Glasgow-born academic, who had also lectured at Coventry University, was depressed at losing his job and had had trouble sleeping.
Miss Orsler said it appeared the professor had "just walked into" the noose as he entered the room. No suicide not was found. Detective Sergeant Peter Reader, of West Midlands Police, said it was possible Dr Connell "wanted to frighten" his partner.
Anthony Lee, clerk to the governors at Wolverhampton University, said Dr Connell had been investigated for an "academic misdemeanour" in January and dismissed in March. The university called the hearing after a student alleged that Dr Connell copied his work.
Recording an open verdict, coroner Dr Richard Whittington, said it was not possible to rule whether the death was suicide or an accident.