Three companies plan to move to a seven-story office building in Clifton, a rare sign of activity these days in the commercial real estate market.

The former Givaudan building on Clifton’s Delawanna Avenue has attracted many new tenants.

The building — at 100 Delawanna Ave. — is fully occupied, and the arrival of two new tenants signals their expansion in a time when the overall economy is contracting.

A total of 280 jobs will be at the building, once owned by the flavor and fragrance giant Givaudan, according to Caren Franzini, who heads the New Jersey Economic Development Authority.

Adapting the building for the tenants also will mean new jobs. Michael Seeve, president of the Mountain Development Corp., which bought the building about seven years ago, said Wednesday the real-estate company would need about 30 more workers over the next year.

Among the tenants moving in over coming months will be the New York-based Telx, which provides data services to companies that need Web servers or additional computer storage.

The Telx data facility is one of at least six other data centers that have sprouted in New Jersey over the last year, including a Switch & Data facility that began operations in late October, according to the development authority. New Jersey, which has about 6 million square feet of space occupied by data centers, reportedly ranks high nationally as a data center hub.

About a half-dozen companies have contacted the Public Service Electric and Gas Co. in recent weeks to inquire about locating their data centers in New Jersey, said Will Steffens, a vice president for PSE&G.

“Growth in this economy? That’s all we’re seeing, basically,” he said.

To accommodate the energy-hungry and heat-producing servers that will be housed at the Clifton office building, PSE&G plans to double the amount of electricity brought into the building — not only for the servers but also powerful heating, ventilation and air-conditioning systems needed to cool the equipment.

Franzini, who spoke at a press conference, pointed to the spot of positive economic news to highlight the state’s willingness to promote the economy.

“New Jersey is becoming business-friendly,” she said.

Automated Logic and EK Success Brands, a division of Wilton Products Inc., were the other two tenants whose leases were announced Wednesday. Automated Logic, which specializes in green energy systems for buildings, plans to move its offices from elsewhere in Clifton, Seeve said. EK, which is also in Clifton, has moved its design and management offices to the building, and is constructing a showroom for companies that buy its crafts.