The two senior members of staff in the university's marketing and student recruitment department were dismissed last December.
They had previously expressed concerns at plans to restructure the department.
The university said it was trying to resolve the matter with the pair and was disappointed at the strike.
The dispute is over the sacking of two staff, Helen Ghaly and Sam Bowker, a union official.
"No institution should be allowed to ride roughshod over agreed procedures and violate its employees' rights in this way," says UCU regional official Martyn Moss.
The UCU believes the pair may have been targeted as a result of their role in the union and has also lodged an unemployment tribunal complaint on their behalf.
The union says some 75% of the staff who took part in the ballot voted in favour of the strike.
In a statement, a University of Salford spokesman said: "We have been trying to resolve this dispute with the individuals concerned and are therefore disappointed that a day of strike action has been called.
"We expect all student lectures to run as normal on Thursday.
"We hope that a resolution can be found but, as this is an ongoing legal matter, we are unable to comment further."

The Scarlet arrived in the country on Monday after interrupting a holiday, before coming off the bench in Tuesday's 40-7 loss to the Chiefs.
He replaces the injured George North, with Liam Williams moving to the wing.
"I've been asked to do a job on the weekend and hopefully I'll be able to do it," said Patchell.
"It's been a bit of a whirlwind few days, but I'm looking forward to the challenge on the weekend.
"It's a really exciting thing to look forward to and I'm sure Saturday night will be bouncing and it will be a great atmosphere to play in front of."
Wales, beaten 39-21 by New Zealand at Eden Park, are looking for a first win over the All Blacks since 1953.
Patchell, 23, trained with the Wales squad before the defeat by England at the end of May, but was not included in the initial tour squad.
But injuries to North and Gareth Anscombe (hip) meant former Cardiff Blues back Patchell was given the call from the Wales camp while on holiday in north Wales.
"This Saturday, I wasn't meant to be doing much, probably watching the game," he said.
"I was actually driving to north Wales with my housemates when I got a phone call telling me I'd probably be required, but thought that I'd be flying on Sunday.
"And then I got a phone call when we were on the first tee at the golf club, saying can you leave the boys in north Wales.
"So I left my two housemates stranded on the first tee, jumped in the car and drove back to Cardiff."
It is the first time Wales coach Warren Gatland has picked Patchell, with his previous two caps coming on the 2013 tour to Japan when Robin McBryde and Shaun Edwards were in caretaker charge.
Patchell is glad to be part of the camp again having missed out on previous Wales squads.
"I'm very, very fortunate that it has come around," he said.
"Injuries put me out of a couple of them and for whatever reason - form, selection - I didn't quite become a consistent member of the squad as I'd hoped I would.
"It's a great opportunity to be back here."
Wings Tom James and Eli Walker started against the Chiefs, but Gatland said his fringe players missed a chance to impress in Hamilton with Patchell subsequently getting the nod for Saturday's game in Wellington.
"He was potentially unlucky not to be on the tour in the first place and we watched him play 15 for the Blues on a number of occasions and we've been impressed with him," said Gatland of Patchell.
"He's quick, he's got a big boot on him and we think he can do a job for us.
"He brings a physical element, he's an intelligent rugby player and he's pretty excited about the opportunity."
Staff at the University of Salford are expected to strike on Thursday in support of two sacked colleagues.
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Rhys Patchell says he has had a "whirlwind few days" after being named full-back in Wales' team to play world champions New Zealand on Saturday.