In a post on his Facebook page, the Parti Québécois leader offered "his condolences" to Couillard following the death of his "former associate."
He also posted old photos of the two men posing side by side, as well as a web link to a Google search page of stories about how they once formed a company together.
Porter died Tuesday at a Panama hospital, where he was fighting extradition to Canada.
He is accused of receiving $11.25 million in secret commissions for rigging the contract to build the new McGill University Health Centre superhospital in SNC-Lavalin's favour.
This isn't the first time Couillard's past connections to Porter have been made an issue by his political opponents.
Couillard faced similar attacks in the lead-up to the 2014 election.
The premier has acknowledged he and Porter set up a company together in 2010, but has said no business was ever conducted and that there were no financial statements before the firm dissolved in 2012.
The post caused a stir on social media, with many saying it lacked class.
In a statement, Couillard's office said the population could draw its own conclusions about Péladeau's comments.