The one-time bank building is home to a variety of tenants, having been repositioned in 2001 by Nordic Properties of Burlington. That firm divested 4 Liberty Sq. in June 2005 for $5.8 million to the group spinning it over to Synergy.

Now starting its fourth year in business, Synergy is fueled by Irish capital, primarily wealthy individuals seeking to take advantage of the higher returns available in the US. Irish money made several substantial buys locally in 2007, although few capital sources were as prolific in the city as Synergy save perhaps for Anglo-Irish Bank. Synergy has now invested more than $500 million in the area, picking up such properties as 141 Tremont St., 141 Portland St. and 27 School St. Most of the investments have been Downtown, but the firm last summer paid $34 million for 25-55 Morrissey Blvd. in Dorchester, a 104,000-sf complex of retail and office space just off the Southeast Expressway. Synergy also owns 10 Fawcett St. in Cambridge's Alewife district.

VP Noah Hano, who joined the company in 2007, reiterates Greaney's expectations that Synergy will be a recognized player again in Boston's investment market this coming year, once more targeting the class B sector that dominates its portfolio. Synergy hopes to ramp up the deal size, he says, likely pursuing investments between $20 million and $100 million. As in the case of 4 Liberty Sq., Synergy will embrace off-market deals, of which Hano says there are a number of prospects already on the radar screen. Even so, he worries that the troubles that dogged sales late in 2007 could extend into the new year, keeping some assets sidelined in the early going.

The purchase of 4 Liberty Sq. was financed by a $6.7-million loan from TD BankNorth. The opportunity was brought to Synergy by Ernest Barrueta of Barrueta & Associates, the same broker who handled the 2005 disposition by Nordic.

The fourth floor of 4 Liberty Sq. is available for lease. Satisfied enough to pay $314 per sf, Synergy was attracted by the building's location and solid tenant base, says Hano, as well as a strong retailer on the ground floor in the Vault Restaurant. "More importantly, it helps us cater to some of the smaller tenants in our portfolio," Hano says of 4 Liberty Sq., an historic building whose 3,300-sf floor plates have attracted a diverse mix of professional and service-oriented companies.