(FORTUNE Magazine) – Like spouses in a healthy marriage, corporations and nonprofit organizations are redefining their relationships to suit a new environment. Once upon a time, corporate largess consisted of one-shot, no-strings-attatched cash gifts bequeathed by the CEO upon a large umbrella organization like the United Way. That's changing as tighter budgets force corporations and nonprofits to craft long-lasting, mutually beneficial agreements. "The tin-cup-beggar approach to fundraising is out," says Susan Elnicki Wade, managing editor of Corporate Philanthropy Report, an Alexandria, Virginia, newsletter. "Companies won't just write checks anymore. They want partnerships that further their goals." Examples: 3M just gave $1 million to the MBA program at the University of Minnesota. Rather than dump the money and run, 3M officials formed a committee with university execs to see how the two organizations could work together long term. Smart move: About 15% of 3M's employees are Golden Gopher alums. Unisys, long a benefactor of Philadelphia's Franklin Institute, one of the nation's largest science museums, is also turning from patronage to partnership. The computer giant has donated computer hardware and software and more than $2 million to the museum since 1988. More recently the two formally agreed to work together on a variety of new projects into the next millennium. Some Unisys employees even have offices at the Franklin, where they work with museum personnel to create programs for student visitors. So far their inventions include a state-of-the-art weather center, an interactive electronic docent, and an Internet-based science service for grade-school teachers. Technologies like that may eventually turn up in Unisys products. Says Unisys VP of public affairs David Curry: "It's a very dynamic relationship. Both cultures are learning from each other."