Versatile actor Hank Azaria has made his mark on TV (“The Simpsons,” “Tuesdays with Morrie”) and movies (“America’s Sweethearts,” “The Birdcage”). The likable actor is a natural for a lead in a TV sitcom.

It’s a shame that Azaria didn’t better develop “Imagine That,” which debuts at 8 tonight on NBC.

In “Imagine That,” Azaria stars as TV comedy sketch writer Josh Miller. At home, he and lawyer wife Wendy (Jayne Brook) are having intimacy problems. At work, he has to deal with idea-stealing boss Barb (Katey Sagal) and his shirt-chasing partner, Kenny (Joshua Malina). (Do you see any original thoughts yet?)

Josh gets many of his ideas from his imagination, and these reveries allow Azaria to trot out a zany assortment of comic characters. “Imagine That” could be an interesting update of William Windom’s classic “My World and Welcome to It,” but it doesn’t go far enough. It’s possible to overdo these fantasy sequences, but Azaria’s show uses them way too sparingly, a tiny dash of spice in a big ol’ kettle of bland.

As co-executive producer with Seth Kurland (“Friends”), Azaria must be held partly to blame. To his credit, he’s surrounded himself with veteran TV actors Brook (“Chicago Hope”), Sagal (“Married … with Children”) and Malina (“Sports Night”). Still, in tonight’s retooled pilot, the chemistry just hasn’t emerged yet.

Perhaps if “Imagine That” had a lower-wattage cast, it could come on the air and be allowed to grow naturally (as an example of that, see NBC’s “Scrubs”). But with Azaria come high expectations, and “Imagine That” doesn’t live up to them. The series is a slight improvement on the sitcom it’s replacing, the critically flambeed “Emeril,” but it’s still not even the funniest show in its timeslot (that would be “That ’70s Show” on Fox).

“Imagine That” may get the time it needs to improve (NBC can only replace so many shows a season). Its talented cast could overcome its hackneyed scripts and meld together. The writers could come up with some funny bits. But that’s a lot of ifs that have to gel.