Inter suffered a first defeat of the season on Saturday, going down 3-1 at home to Udinese and leaving the door ajar for Massimiliano Allegri's men to leapfrog them as closest challengers to leaders Napoli.
It was an opportunity the champions were forced to approach patiently at first but Bologna's resistance and ambition appeared to desert them entirely once Pjanic's 27th-minute free-kick had got the better of goalkeeper Antonio Mirante.
The Bosnia-Herzegovina playmaker turned provider with an excellent lofted ball for Mario Mandzukic to double the lead before half-time and any remaining doubt over the destination of the points was extinguished when Blaise Matuidi emphatically smashed in his first Juventus goal in the 64th minute.
Napoli's advantage at the summit is now trimmed to one point as Allegri's squad with reams of title-winning knowhow prepare for next weekend's match against Roma – a crunch clash that arrives after a midweek Coppa Italia assignment versus Genoa.
Allegri again opted to leave Paulo Dybala on the bench and Juventus had a solid grip on possession during the first 25 minutes without creating any chances of note.
A Bologna counter-attack saw Godfred Donsah test Wojciech Szczesny's handling with a firmly struck shot but Juve had their set-piece specialist on hand to succeed where they had failed until that point from open play.
Mattia Destro brought down Alex Sandro on the left-hand corner of the penalty area and Pjanic curled a free-kick inside the near post that Mirante could only palm into the net.
Juve swiftly doubled their advantage in the 36th minute, with Pjanic to the fore again as he picked out Mandzukic with a sublime raking pass.
The Croatia forward chested down impeccably and hooked a shot towards the far corner despite some close attention from Ibrahima Mbaye. Once more, Mirante got a hand to the shot but was unable to alter the outcome.
Bologna boss Roberto Donadoni had his decision to replace striker Destro with Bruno Petkovic whistled in the 53rd minute and the closest a home player came to putting the ball in the net before the hour was when Filip Helander almost prodded Alex Sandro's cross into his own goal.
Helander's attempts to clear the next cross from the Brazil full-back also left much to be desired when he shovelled a bouncing ball in the direction of Matuidi, who lashed unforgivingly into the bottom corner to ensure Juve would make it four wins from their last five top-flight away games.
Some wasteful finishing from Gonzalo Higuain prevented Juve from running up a more handsome scoreline, while fellow attacker Mandzukic limping off with 15 minutes left gave cause for some concern.
But the sight of a player as wonderfully gifted as Dybala coming on in his place and streaking clear of Bologna defenders to fire narrowly over underlined the fact that Donadoni's worries, after six defeats the last nine, might be somewhat greater.
