While DC has so far struggled to make a big-screen impact beyond Superman and Batman, it's consistently had more success with episodic television. Smallville (Superman) gave way to Arrow (Green Arrow), which is soon to be joined by The Flash and the pre-Batman Gotham, about Commissioner Gordon and the Gotham PD. Now NBC are getting in on the action, developing a series based on John Constantine, star of DC/Vertigo's Hellblazer series. David S. Goyer (who else?) is writing the pilot, with Mentalist exec-producer Daniel Cerone.
John Constantine, the cynical, manipulative, trenchcoated, chain-smoking urban magician, was created by the legendary Alan Moore in 1985, as a supporting character in his famous Swamp Thing run. It was Swamp Thing's title, but the scene-stealing Constantine immediately became the story's engine, installing himself essentially as Swamp Thing's manager in an arc involving the Brujeria: a black magic chaos cult who had quietly taken over the world and were next intent on the destruction of Heaven.
Constantine grew to the extent that he was given his own series in 1988 (initially to be called Hellraiser until a certain Clive Barker film forced a re-think). With Moore disinclined to write it himself, the job fell to fellow Northampton resident Jamie Delano, whose lengthy run was followed by sterling work from Garth Ennis, Paul Jenkins, Warren Ellis, Brian Azzarello, Mike Carey, Denise Mina, Andy Diggle and Pete Milligan (among many others, including Neil Gaiman). After 25 years, post DC's New 52 re-jig, Hellblazer was retired last February at issue 300, and Constantine was folded into regular DC continuity, both in his own more mainstream series, and as part of the Justice League Dark.
There was, of course, a Constantine film in 2005, which got some things right, but re-cast the Liverpudlian Sting-lookalike Constantine as Keanu Reeves, turned his taxi-driving compatriot Chas into a teen sidekick (Shia LaBeouf), gave him a crucifix-shotgun and had him pack in the gaspers. A television series then has every opportunity to do the thing properly - even if somewhere like HBO would seem a better home for sweary fights with demons than primetime NBC. There's also scope for appearances by other characters in the DC pantheon: Swamp Thing, obviously, but Constantine has also encountered Shade, Sandman, Animal Man, Zatanna, The Phantom Stranger and various others (including Batman).
Where this leaves Guillermo Del Toro's own mooted Justice League Dark project is unclear, although given that DC's TV and film projects have hitherto not interconnected, it's possible a movie and a show could exist independently, side-by-side. What we do know is that Goyer and Cerone have a "script plus penalty" deal, which means they get paid for the script, plus more if the show doesn't go into production. That means it's often more economical for a studio to actually make a show than not make it. So the signs are good for Constantine to at least reach the pilot stage. We'll keep you posted.