When 2010’s “Black and Yellow” gifted Wiz Khalifa with a multi-platinum chart-topper—and 2011’s Rolling Papers earned him a major commercial breakthrough to match—the Pittsburgh rapper had a tough act to follow. His fourth studio album may broaden and gloss up his smoke-shrouded pop-rap sound with more guests and a bigger budget, but the rapper retains his knack for low-slung mantras celebrating the mellowing effect of weed and other daily indulgences. Around half the tracks are still helmed by his long-time collaborators from Pittsburgh production crew ID Labs, whose dazed synth pulses are the perfect accompaniment to Wiz’s hypnotic drawl and amiable storytelling. As for the lyrics, this is practically a concept album about the transformative jolt of sudden wealth and fame. Riffing on Prodigy’s 2000 outing H.N.I.C., the title stands for “Only N**** in First Class”, a phrase that comes up more than once as Wiz observes how much his circumstances have changed since his last record. “Paperbond” shrugs off the hip-hop adage “Mo money mo problems,” while “Bluffin” deals with how his money inspires jealousy. At nearly 10 minutes long, “No Limit” includes a heady midsection of New Age synths as the rapper punctures others’ perceptions of him. The guest spots are well-chosen, including slick vocal hooks from Akon, Cam’ron, 2 Chainz, and Three 6 Mafia’s Juicy J. The upbeat romance of “Got Everything” flexes a starry-eyed R&B turn from Courtney Noelle, whereas lead single “Work Hard, Play Hard” reunites Wiz with his “Black and Yellow” collaborators Stargate alongside Benny Blanco. Pharrell helms and also features on “Rise Above,” a surprisingly soft ballad that enlists Tuki Carter and Wiz’s then-partner Amber Rose. Especially effective is “Remember You,” with Illangelo and Dpat conjuring a trippy, tempo-bending backdrop for The Weeknd’s weepy falsetto and extended lovelorn storyline. Clocking in at more than an hour long in its original version, O.N.I.F.C. grants Wiz Khalifa generous time to stretch out and expand upon his signature themes. He’s still game to crack a stoned laugh, and the prominent synths evoke an indulgent club experience slowed down by chemical enhancement. Yet as much as the rapper salutes his narcotic of choice, weed isn’t just a staid presence here. It’s more like the creative prompt that sets this newly minted star on a quest to examine everything that’s changed since he became a household name.