Darlington have parted company with manager Mark Cooper and his assistant Richard Dryden following Saturday's 3-1 defeat by Braintree Town.
Cooper and Dryden, both 42, led the Quakers to FA Trophy success at Wembley in May but have struggled this season, losing eight of 18 games this term.
"Results have been nowhere near where we wanted them," chairman Raj Singh told the club website.
"Our ultimate aim this year was promotion, and we're nowhere near."
Singh added: "Our recent results have been closer to relegation form than promotion form, which has been baffling."
The former Tamworth, Kettering and Peterborough boss arrived at the Arena in June 2010 following the departure of Simon Davey and Ryan Kidd, and just missed out on the play-offs in his first season in charge, as well as beating Mansfield in the FA Trophy final to seal the club's first silverware.
Following their Wembley success the club were among the favourites for promotion, yet disappointing defeats by Southport, Bath City and Braintree Town have seen Darlington slump to midtable following a bright start.
In addition, Cooper was given the finance to sign players such as former Malaga defender Jonathan Sanchez-Munoz, Exodus Geoghagon and John Campbell, signings that have been unable to stem the slide down the table.
However, as recently as this month the Quakers board offered their backing to Cooper, although Singh has defended his decision.
"I supported Mark with a strong budget and I backed his judgement in bringing in a number of new players, even up to last week when we brought in two new players, because we wanted to give him every chance to turn this around.
"I decided to publicly back Mark a fortnight ago and we were lifted by wins over Stockport and Kidderminster, but the last two results and, more importantly, the manner of the defeats were, for me, the final straw.
"Mark and Richard worked tirelessly to make it work but it just wasn't happening and, as everyone knows, football is a results business.
"We leave on good terms. Mark was a pleasure to work with, I consider him a friend and I wish him all the best in the future."
Singh also confirmed the club hope to make an appointment prior to the Blue Square Bet Premier game with AFC Telford United on Saturday, 5 November.