The home planet of the blue-skinned Benzites, a Federation world whose atmosphere differs from the usual standard and which was occupied by the Dominion until freed by the Romulans.
Benzar is the homeworld of the Benzites, introduced in the Next Generation episodes Coming of Age and A Matter of Honor through the Starfleet candidate Mordock and the exchange officer Mendon. Benzites of that era wear a small breathing device off-world because their native air is unlike that of most Class M planets.
In Star Trek: Discovery's Choose Your Pain, the USS Discovery is credited with breaking a Klingon supply line at Benzar during the war of 2256.
The planet fell to the Dominion during the Dominion War. In the Deep Space Nine episode The Reckoning (2374) it has just been liberated by the Romulans, and there is some unease among the allies about whether Romulan forces will be willing to leave again.