Casino mogul Steve Wynn handed out $100,000 to Gov. Charlie Baker’s anti-pot legalization campaign one day before the state Gaming Commission gave the green light to Wynn’s planned Everett casino development, records show.

Wynn Resorts’ large donation was received by the Campaign for a Safe and Healthy Massachusetts on Tuesday, just 24 hours before the massive casino complex got final approval, clearing the way for construction to begin soon.

Baker, along with Boston Mayor Martin J. Walsh and House Speaker Robert A. DeLeo, formed the committee to defeat Question 4 — which would legalize the recreational use of marijuana for adults 21 and over — and has made it a major political priority.

The governor partly controls the Gaming Commission, which voted unanimously on Wednesday to approve the controversial casino development. Baker also stepped into the casino fight earlier this year to resolve a dispute between Wynn and state environmental regulators.

Wynn’s $100,000 contribution is his first to Baker’s anti-pot campaign, which has drawn support from numerous business leaders and development companies regulated by the state, as well as dozens of Bay State elected officials.

A spokesman for the campaign to legalize marijuana said the Wynn donation to Baker’s ballot question committee raises questions about whether he and other developers might be trying to “curry favor” with the administration.

“I have never seen a governor formally create a committee in order to oppose or support a ballot question,” said James Borghesani, spokesman for Yes on 4. “This is very unusual in Massachusetts politics.”

Robert DeSalvio, president of Wynn Boston Harbor, said the contribution “is solely based on the serious regulatory and human resource challenges that our company would face” if marijuana as legalized.

DeSalvio said the passage of Question 4 would also make it “extremely difficult” to enforce the company’s no-drug policy at Wynn casinos.

Baker himself has put his clout on the line for the No on 4 campaign and has solicited contributions to back the effort to stop the legalization of pot. His top campaign strategist, Jim Conroy, is also the lead consultant for the campaign against Question 4.

Baker also recently came out against Question 1, which would allow another slots parlor in Revere. Wynn has led the campaign to defeat that ballot question, which would open the door for a competing gaming facility just a few miles from his Everett casino.

Several casino operators have gotten involved in this year’s state ballot campaigns.

Another Las Vegas casino magnate, Sheldon Adelson, recently gave $1 million to another Baker-backed ballot campaign in support of Question 2, which would lift the cap on charter schools.

Many business leaders and construction companies, including the charitable arm of Suffolk Construction, which is building Wynn’s casino, have also given to the charter school campaign.