TBS announced today that it was canceling Lopez Tonight, the late-night vehicle for George Lopez that debuted in November 2009. For its 21-month-run, Lopez Tonight served as the only true successor to Arsenio Hall’s old late-night show on FOX, both in terms of energy and diversity.

Here is the brief statement from the network:

“TBS has reached the difficult decision not to order a third season of Lopez Tonight. Thursday will be the final episode of the show. We are proud to have partnered with George Lopez, who is an immensely talented comedian and entertainer. TBS has valued its partnership with George and appreciates all of his work on behalf of the network, both on and off the air.”

When TBS brought Conan O’Brien in last year and bumped Lopez to midnight, Lopez held onto 883,000 viewers in the 18-49 demo and 571,000 in adults 18-34. And Steve Koonin at the time expressed confidence that “TBS will be a top late-night destination for young adults.”

By May 2011, however, Lopez was averaging only 295,000 viewers among adults aged 18-49, losing two-thirds of that audience from the previous November. The only late-night TV talk show Lopez was beating with any regularity was Mo’Nique’s, which BET halted production on last month.

For his final show, the previously announced guests include Raven-Symone and comedian Auggie Smith.