They say they are ready to restore the crumbling old council headquarters and courthouse to its former glory but need the council to help by issuing the owner with a compulsory purchase order to secure the Grade II-listed building and return it to public hands.
The Friends of the Old Town Hall says it is ready to raise the money for the purchase, by inviting Sheffielders to snap up community shares making them become part owners, before securing grants to cover restoration costs estimated to be in excess of Â£10 million.
But unless the council is willing to work with it and use compulsory purchase powers, the group says its grand plans for the iconic building on Waingate will remain a dream.
Valerie Bayliss, who chairs the friends group, says it needs the council's help as the building's owner G1 London Properties, which is rumoured to be preparing plans to convert the premises into luxury apartments, has never responded to any approach from the group.
"We are ready not only to raise the purchase price but to start the hard work of raising grants for the restoration costs," she said.
"We are looking for a serious commitment from the council to start this journey with us. It's the only way for Sheffield to be certain this great building can be restored to its former glory."
The call came as the group voiced serious concerns about the long wait for 'urgent' repairs to the leaking roof, which it fears may now not happen before winter despite the council having announced funding for the work last summer.
The delay was initially blamed on difficulties securing a key from the owners, while the latest hold-up is believed to be down to the building's parlous condition making it hard to inspect the roof safely in person.
The Old Town Hall was built in the early 1800s and was used as a courthouse after the current town hall opened in 1897.
It has been disused since 1997 and was bought by G1 in 2004. In 2007, it was included in the Victorian Society's list of the 10 most at-risk buildings.
The friends group has drawn up proposals to restore the building in phases, creating a performance space, restaurant and offices, among other facilities.
The Star has contacted Sheffield Council and attempted to contact G1 London Properties for a comment.