Their rendez-vous follows a second cancellation of the game on successive evenings in Buenos Aires.
Saturday night's match was postponed after River Plate fans attacked the Boca team bus with stones and pepper spray near River Plate's Monumental stadium.
Several Boca players were hurt in the attack.Competition organisers, Conmebol, intially wanted to delay Saturday night's kick-off. But with the tie balanced at 2-2, it became clear that Boca's squad was still recovering from the assault.
Sunday's game was also postponed for similar reasons.
"There isn't a level playing field to play the final. That is why Conmebol have taken the decision to postpone the final of the Libertadores," Conmebol president Alejandro Dominguez said.
Boca say they want River Plate punished over the incident. "Matches are won and lost on the pitch, that's my personal perspective," said Boca president Daniel Angelici. "But I have a responsibility as club president and that's why I have to stick to the statute."
Among the sanctions available under the governing body's rules are disqualification from competitions and bans from future tournaments. A club cabn be fined or have points deducted. A game can also be played without fans in the stadium.
Three years ago, Conmebol sanctioned Boca after their fans attacked River Plate players with pepper spray at half-time of a Copa Libertadores quarter-final tie. Boca were kicked out of the competition with River progressing.
Finding a new date to complete the 2018 final will be complicated. The Group of 20 summit takes place on 30 November and 1 December in Buenos Aires. It will require a huge security ring in the city with presidents from the United States, Russia and China all expected.
The Copa Libertadores winners are also due at the Club World Cup in the United Arab Emirates between 12 and 22 December.