Sinclair, which owns 192 stations, said in May 2017 that it planned to acquire Chicago-based Tribune's 42 TV stations in 33 markets.
"In light of the FCC's unanimous decision, referring the issue of Sinclair's conduct for a hearing before an administrative law judge, our merger can not be completed within an acceptable timeframe, if ever", Tribune CEO Peter Kern said in a statement.
Last month, FCC Chairman Ajit Pai expressed "serious concerns" regarding this merger, which would have created one of the largest broadcasting companies in the country and further consolidated the power of Sinclair, which owns almost 200 local stations throughout the US.
The $3.9 billion buyout of Tribune Media by Sinclair collapsed Thursday, ending a bid to create a massive media juggernaut that could have rivaled the reach of Fox News.
Sinclair refused to sell stations in the markets as required to obtain regulatory approval, according to Tribune's release, prompting the FCC to put the merger on indefinite hold.
"In an effort to maintain control over stations it was obligated to sell if advisable to obtain regulatory clearance, Sinclair engaged in belligerent and unnecessarily protracted negations with DOJ and the FCC over regulator requirements... all in the service of Sinclair's self-interest and in derogation of its contractual obligations", the suit alleges. Sinclair was to have acquired Tribune for a hefty $3.9 billion price tag - in a move that would have added dozens of local stations to the roughly 200 which are already in its portfolio.More news: Indonesia quake : Death toll mounts to 98
More news: Boris Johnson was RIGHT on burka ban comments, senior Imam says
More news: China, Germany defend Iran business ties as US sanctions grip
There was still a slim chance that Sinclair could save the merger because the FCC referred the deal to an administrative law judge.
The Maryland company did not immediately respond early Thursday to a request for comment from The Associated Press. It announced plans previous year to merge with Chicago-based Tribune, a deal that would have given Sinclair access to 72 percent of American households. The Tribune deal, plus other pending acquisitions, will give Sinclair a total of 233 TV stations.
Under the terms of the deal, Tribune and Sinclair had the right to call off the merger without paying a termination fee if it was not completed by August 8.
If no divestitures were made, "the combined company would reach 72 percent of USA television households and would own and operate the largest number of broadcast television stations of any station group", the FCC notes.
The two companies had until midnight Wednesday to call off their deal.
Sinclair has defended the decision to have its anchors read from the same script across the country as a way to distinguish its news shows from unreliable stories on social media.
The FCC's concerns followed similar questions raised in separate filings by the American Civil Liberties Union and conservative news outlet Newsmax Media.