Following defeat to Boston United in last weekend’s play-off semi-final, the Iron have moved to make a change.
The club say they are looking “towards sustainability, and bringing expenditure in line with the level what the football club can afford”.
Dean joined the club from Peterborough Sports in January 2023 but couldn’t keep them up last term.
Despite being one of the favourites for promotion, Scunthorpe were unable live up to expectation - and will be playing Step 2 football again next season.
They will do it under new management with coaches Chris Plummer and Ant Coombe also leaving.
Owner and chairperson Michelle Harness said: “To be saying goodbye to Jimmy, Chris and Ant is undoubtedly one of our toughest decisions since we took ownership of the club, and it is a decision we’ve made with a very heavy heart.
“We inherited significant debt, along with a budget and payroll which by far exceeds the level that we are currently operating at, and we need to work hard this summer to bring that back to a level where we can both compete at, but also remain sustainable, and this must start at football management level, and then focusing on the playing staff.
“We remain wholly committed to recruiting and retaining players for the 2024-25 season who fall within our budget, and will give us the best possible chance to see us competing at the top of the league again.
“Jimmy, Chris and Ant have conducted themselves brilliantly throughout our time at the club, and will always be welcome at the Attis Arena should they wish to visit us. I would like to personally thank each of them for their hard work and endeavours while they represented our Board, the badge, and most importantly, you as the fans of Scunthorpe United.”