The hotel group aims to the property open as a four-star hotel in early 2020, as it plans a multi-million euro refurbishment.
The reopening of the Dublin hotel is expected to create up to 70 permanent jobs and is the second hotel purchase by TMR Hotel Group in the Tallaght area.
Earlier this year, the group brought two four-star-hotels- the Plaza Hotel in Tallaght and Harvey’s Point in Donegal.
TripAdvisor has also ranked Harvey’s Point, Donegal, as “No 1 Hotel in Ireland” for the past six years.
TMR said that investing in the three hotels will cost approximately €60m (£51.8m)
Eimear Fox, director of TMR Hotel Collection said: “Over the coming months we will implement a multimillion euro investment programme at our Tallaght Cross and Plaza Tallaght hotels which we see as a major vote of confidence in the area and a substantial boost to tourism and the local economy.”