From the Morning Memo:

As he battles to keep his seat in a four-way race and running solely on the Independence Party line, Sen. Mark Grisanti is getting some last-minute financial help from eyebrow-raising donors who funneled their contributions through a New York City-based environmental group.

The Buffalo Republican’s biggest benefactor was former NYC Mayor Mike Bloomberg, who recently penned a $350,000 personal check to the New York League of Conservation Voters with the understanding that the bulk of that cash would go to help Grisanti, multiple sources confirmed.

Bloomberg pledged to protect Grisanti and three other Republican senators who crossed party lines back in 2011 to vote “yes” on same-sex marriage. Grisanti is the last remaining member of that quartet still in the chamber.

The former mayor had already maxed out in his contributions to Grisanti for both the primary and general elections. So he turned to the NYLCV, with which he had a close working relationship during his years at City Hall.

Bloomberg spokesman Howard Wolfson confirmed the mayor’s contributions, and said he gave to the NYLCV because it is “doing good work” in the 60th SD.

Bloomberg, a billionaire Democrat-turned-Republican-turned independent, was once the largest personal contributor to the Senate Republicans, but hasn’t given them much support as a group since he departed City Hall at the end of last year.

The former mayor is still involved in politics, but his focus is now mostly national. He has been spending millions of dollars to support House, US Senate and gubernatorial candidates on both sides of the aisle, as well as on various ballot initiatives across the country this cycle.

Bloomberg’s cash accounts for about half of the approximately $700,000 worth of independent expenditures the League plans on spending on this year’s elections. That’s about twice the amount it spent in 2012.

This isn’t the first time Bloomberg and the NYLCV have teamed up to help Grisanti. In 2012, the League made Grisanit’s re-election immediately after the senator’s “yes” vote on same-sex marriage one of its top priorities, and co-hosted a fund-raiser for him at Bloomberg’s Upper East Side townhouse. The organization spent in the six figures to assist Grisanti’s successful campaign that year.

The NYCLV recently named Grisanti its third priority Senate candidate in the general election – along with Long Island Democrat Adrienne Esposito and freshman Democratic Sen. Ted O’Brien, of Rochester. The outcome of any – or all three – of those races could play a big role in the fight for control of the Senate.

Technically speaking, however, the League isn’t taking sides in that fight, preferring instead to endorse on a case-by-case basis, supporting lawmakers it believes have backed its agenda in Albany.

Grisanti chairs the Environmental Committee in the Senate, while O’Brien is the ranking member on that committee. Esposito is a long time environmental activist.

The NYLCV has already paid for one TV ad in support of Grisanti, and will soon hit the airwaves with another, a spokesman confirmed. Also on tap: Mailers and an extensive GOTV effort on the senator’s behalf.

The NYLCV also received a $150,000 contribution from the IDC’s PAC. IDC leader Jeff Klein has been courting Grisanti since the GOP senator lost his party’s primary in September to attorney Kevin Stocker.

The League also got a check for $5,000 from environmental attorney Larry Rockefeller, a moderate Republican who recently crossed party lines to endorse Democratic Gov. Andrew Cuomo and appeared in a campaign ad on the governor’s behalf.

Crain’s, which first reported Bloomberg’s contribution to the NYLCV, noted that both the real estate industry and the teachers unions, which are spending big to help opposite sides in the Senate fight, have given money to the League’s PAC.