“Basic publishing is absolutely important, but it’s not very exciting,” said Mr. Blackwell, who speaks in a slow, soft British accent but carries two cellphones that chirp constantly. “But now it is the music business. Record companies used to manufacture, and that was the difference between a record company and a publishing company. All that is really gone now.”

Under the deal, Primary Wave will control 80 percent of Mr. Blackwell’s share of two catalogs: Marley’s songs and Blue Mountain Music, a publisher that Mr. Blackwell set up in 1962, which has reggae hits by Toots & the Maytals and rock classics by Free (“All Right Now”) and Marianne Faithfull. Blue Mountain also has rights to U2 songs, but those are excluded from the deal, Mr. Blackwell said.

Primary Wave has carved out a lucrative niche in music publishing by focusing on aggressive branding and marketing campaigns for what its founder, Larry Mestel, calls “the icons and legends business.” The company has a relatively small catalog of about 12,000 songs — its roster includes Smokey Robinson, Def Leppard and Steve Cropper, who wrote “(Sittin’ On) The Dock of the Bay” with Otis Redding — that it promotes heavily through commercial tie-ins, movies and TV shows.

Mr. Mestel, whose first job was working for Mr. Blackwell at Island, declined to offer any specifics about his plans for the Marley songbook. As examples of his company’s approach, he cited two past campaigns. When Primary Wave managed Kurt Cobain’s catalog, it struck a deal with Converse to drape sneakers in Nirvana lyrics; for Aerosmith, the company helped create a state lottery game, with each scratch-off card revealing words from Aerosmith songs.

For the estate of the pianist Glenn Gould, Primary Wave plans to send a hologram of Gould — who died in 1982 and famously hated playing live — on a concert tour.