One of the men named in the ITV Exposure programme, to be broadcast on Monday night, is the convicted IRA bomber James Francis Gavin, who has since died.
In Hunt for the Birmingham Bombers, Gavin, a former British soldier, is alleged to have been one of the people who planted the bombs.
The second suspect is shown being asked about his alleged role by the documentary makers outside a Belfast supermarket. He declined to comment and his lawyers told the programme: Our client denies all the allegations … and does not intend to respond any further to the unfounded allegations you have made.
Documentary claims to have identified suspected IRA pub bombers
The documentary will suggest the Crown Prosecution Service had examined the case against the suspect and concluded there was insufficient evidence to charge him.
A botched criminal investigation by West Midlands police immediately after the atrocity led to the jailing of the Birmingham Six, one of the most infamous miscarriages of justice in English legal history. Their convictions were quashed in 1991 after a long battle by campaigners, including the MP and journalist Chris Mullin.
Julie Hambleton, whose 18-year-old sister Maxine was killed and who leads the Justice4the21 campaign, told the programme: What do I want? Me, personally, I want the bastards who killed my sister and the other 20 to be brought to justice, short and simple.
She added: We could have walked past him when we were in Belfast. When people ask you howd you feel if you met them or saw them, you can never answer that question.
Ms Hambleton said: What do I want? Me, personally, I want the bastards who killed my sister and the other 20 to be brought to justice, short and simple.
The court of appeal ruled last week that a coroner had been right not to name any alleged perpetrators in fresh inquests.
ITVs Exposure programme will tonight (Monday) reveal evidence pointing to two prime suspects in the 1974 Birmingham pub bombings.
For more than four decades, mystery has surrounded the identities of the men who planted the bombs which killed 21 people and injured more than 200.
One of the men named in the ITV Exposure programme, to be broadcast on Monday night, is convicted IRA bomber James Francis Gavin, who has since died.
As recently as last week, the Court of Appeal ruled in favour of coroner Sir Peter Thornton QC, deciding that an investigation into who was responsible would not form part of the inquest into the victims deaths.
But now an extensive ITV investigation names former British soldier James Francis Gavin and Michael Patrick Reilly as the prime suspects for planting the bombs. Reilly has never before been publicly named as a suspect. Gavin has been named previously in connection with the bombings but not as a bomb-planter.
The programme, The Hunt For The Birmingham Bombers, which airs at 10.45pm on ITV, features reporter John Ware confronting Reilly about the allegations outside a supermarket in Belfast.
The investigation has built on the work of former Government minister, Chris Mullin, who campaigned for the release of the wrongly convicted Birmingham Six.
Mullin twice interviewed a man who admitted to the bombing on the condition that he would never reveal his name.
And he hasnt… but through cross referencing information in Mullins book with police transcripts and birth records, speaking to witnesses and a former IRA man, journalist John Ware believes the evidence points to Reilly and Gavin.
Reilly, who was a teenager living in Birmingham at the time of the bombing, was interviewed by West Midlands Police in 1975.
He admitted bombing some local businesses in Birmingham and that he knew about the bombings in advance, but he did not admit to being involved. He was sentenced to 10 years in prison for conspiracy and causing explosions.
After his release he moved to Northern Ireland. ITV tracked him down to Belfast where he was confronted with the allegations, which he denies.
Reillys solicitor told ITV: "Our client denies all the allegations … and does not intend to respond any further to the unfounded allegations you have made."