The exact breakdown of the financial input of the residents has not been revealed.
The two-acre Georgian square in Ranelagh had been listed for sale at the Allsop Space auction in the Shelbourne Hotel yesterday, but failed to sell under the hammer with no bids coming from the floor despite four bidders stumping up the €14,000 deposit to be eligible to bid.
Allsop auctioneers said that four pre-registered bidders were at the auction and following negotiations, a sale to a party in trust was concluded.
Earlier, a Dublin City Councillor confirmed that negotiations had taken place between the council and the sellers of Dartmouth Square to secure the space for public ownership.
Labour Cllr Mary Freehill said the council did not bid at the Allsop auction because it did not want to put up the price when spending public funds.
Ms Freehill said the square in Ranelagh was the subject of zoning orders that prevent building, along with tree preservation orders, so the space would not be of interest for development.
Former owner Noel O’Gara attended the auction.