"I'll start thinking about something and, once the idea takes hold, it usually doesn't go," he says, adding that themes of power and rapid technological change seem to be "asserting themselves" in his present writing.
It won't be pitch black in the theatre, but it may be darker than other stage shows and he's interested in the ways in which imagination fills in the gaps. Sinclair is quick to say the show's not bleak, but more about freedom and redemption.
With a 17-strong cast, directed by regular collaborator Elena Stejko, he says it's exciting to work on a project where more people on stage also adds to the atmosphere.
"You can get some amazing dynamics going on with that many people."
Between the comedy of Ladies Night, written with Anthony McCarten, and the sci-fi darkness of Remain in Light, there isn't much Sinclair hasn't tackled: historical dramas, adult comedy, surrealist fantasy; they're all on his CV along with poetry, a children's story and a novel.
While Sinclair's been working on Remains in Light, he's also been researching for his next project. It's an historical novel set in Britain where, from the late 4th century, Roman rulers came under increasing pressure from barbarian insurgents.
He hopes to travel to Britain later this year to complete the research.
What: Remain in light
Where & when: Pumphouse Theatre; February 25 - March 4