Before 321 W 44th St became an office building, it was known as The Record Plant, the cool place to record in the '70s and early '80s. Check out how East End Capital has reinvented it again, plus a look at the rooftop room where John and Yoko used to chill out.

The Plant is in a tech hub, two blocks from Yahoo and Microsoft, says Jonathon Yormak, whom we snapped on one of the 27k SF floorplates and who founded East End with Dave Peretz in 2011. The pair and frequent equity partner GreenOak Real Estate bought the 245k SF, Class-B office building between Eighth and Ninth avenues in December 2012 for $93M, then put $7M into renovations with tech and media tenants in mind, giving the property a modern vibe and its own brand.

Cash flow was fine under Kushner, the previous owner, Jonathon says. But Jonathan wanted to do more, and the shift in office demand drivers from law and finance to tech and creative industries has given him an opportunity to apply a specific vision to what had been a vanilla building.

Interactive Corp moved its About.com office into 3,000 SF here last week, and JLL’s Scott Panzer (right, whom we snapped with East End construction head Nick Polito), is trading paper on five new leases for pre-builts between 5,000 and 9,000 SF. Scott tells us the tenants looking for the retro-cool buildings made popular by Midtown South won’t find many options there anymore. Hence East End’s redo in Midtown.

The company enlisted the pair of Brooklyn artists known as FAILE to paint this mural on the side of the building that faces Times Square, a nod to the creative types East End wants to draw in.

Guns N’ Roses, Aerosmith, Jimi Hendrix, and Bruce Springsteen recorded in the building. And John Lennon, who was on his way home from The Plant the night he was killed, used to rehearse with Yoko Ono and relax in the rooftop room we snapped above. Now it’s a conference room stocked with a catering kitchen to facilitate rooftop events. The music industry still has a presence in the building, too, with Diddy (or the artist formerly known as Puff Daddy) and, in Lennon’s studio, Sony Music Entertainment’s Battery Studios.

Jonathon tells us tenants have already requested dates for events on the expansive rooftop, which also has bathrooms, wifi, a sound system, and outlets for laptops. (Lennon may imagine there's no heaven, but if there is, it's got outlets on the roof.)