After more than four years of planning and construction, Rosenkranz Hall — designed by the Boston-based architecture firm Koetter Kim & Associates — is finally ready to celebrate its official opening this evening.

The building, which has been in use since the beginning of the semester, is the new home of the Political Science Department, the MacMillan Center for International and Area Studies, and the Jackson Institute for Global Affairs. The architectural design of Rosenkranz Hall accommodates the separate identities of its different users, principal architect Mark DeShong said. For this reason, Rosenkranz incorporates a large open lobby and two four-story atria that allow occupants full views of the building’s offices and classrooms, DeShong explained.

But not everyone is comfortable with this openness, students interviewed said.

“It’s nice to have the open space, but it feels a little bit like being in a zoo,” political science graduate student Leonid Peisakhin GRD ’12 said. “Everyone can see into each other’s office, like animals in a cage.”

Late Thursday afternoon, just over 24 hours before the building’s opening gala, the structure still featured a number of “Wet Paint” signs and construction ladders.

But that is not to say the building has not been unveiled yet.

Though it officially opens today, Rosenkranz has been in use since the start of this academic year. While construction workers continued working on the building’s finishing touches as recently as Thursday, professors have decorated their offices with family photos, and lectures and midterms have taken place in the building’s classrooms all semester.

“[The construction] has taken longer than we expected,” political science professor Jessica Weiss said. “But it’s been an easy process.”

The delays in construction were unavoidable, DeShong said, because the University made a number of revision requests last fall — midway through the construction process — as a result of budgetary cutbacks in the face of the economic downturn.

“We were asked to add the Jackson Institute into the building, which was not originally intended to be hosted in the building,” DeShong said.

To accommodate this request, the first floor area adjacent to the building’s passageway to Luce Hall was redesigned last fall, making the space functional as the reception area for the institute.

The building, which has been LEED-silver certified, makes a number of environmental strides to cut down its heating costs: an energy-efficient system installed in the building simultaneously uses heating and cooling mechanisms to equilibrate the temperature of the building. Rosenkranz also uses energy-efficient insulating glass panels.

Commenting on the spatial function of the new structure, Dean of the School of Architecture Robert A.M. Stern ARC ’65 said the new pathway created by Rosenkranz, which connects Prospect Street and Hillhouse Avenue, will help to connect the planned new residential colleges to central campus.

Rosenkranz Hall is named after its major donor, Robert Rosenkranz ’62, who is the CEO of the Delphi Financial Group.