At least 23 of them were shot in clashes between police and protesters that erupted after Delwar Hossain Sayedee, the Jamaat-e-Islami party's vice president, was found guilty of war crimes, including murder, arson and rape.
Sayedee is the third person to be convicted by the controversial domestic tribunal whose previous verdicts have also been met with outrage from Islamists who say the process is more about score settling than delivering justice.
Thursday's death toll was compiled by sources after talking to police in the 15 districts where protests turned deadly. They were the most violent political clashes in more than two decades in the impoverished country's history.
The latest unrest brought the overall death toll to 50 since the first verdict was delivered on January 21.
Among Thursday's dead were four policemen, two of whom were beaten to death after protesters hurled small homemade bombs at a police station in Gaibandha in Bangladesh's north and attacked it with sticks, local police chief Monjur Rahman said.
"At least 10,000 Jamaat supporters attacked us. We were forced to open fire," Rahman told sources.
About 300 people, including scores of policemen, were also injured, doctors, police and local media said.
Police also reported attacks on several Hindu homes and temples by Islamists in the southern Noakhali and Chittagong districts. One old Hindu man was killed in the attack in Chittagong, district police chief Hafiz Akter told sources.
Security forces had been braced for trouble ahead of the verdict against Sayedee, who reacted to the judgment by saying it had been influenced by "atheists" and pro-government protesters who have been demanding his execution.
Sayedee, now best known in Bangladesh as a firebrand preacher, was convicted for setting ablaze 25 houses in a Hindu village and abetting the murders of two people including a Hindu man, according to a copy of the verdict.
He led a pro-Pakistani militia who abducted three Hindu sisters and raped them for three days at a Pakistani camp, said the verdict. He also forced at least 100 Hindus to convert to Islam and made them say Islamic prayers, it added.
His lawyer Tajul Islam described the verdict as "a gross miscarriage of justice", adding that Sayedee did not live in the town at the time when the alleged crimes took place.
"It's a case of mistaken identity. We're stunned. We're going to appeal the verdict," he told sources.
Under a newly amended war crimes law, the appeal process must be completed within 90 days, meaning Sayedee would be hanged later this year if the country's highest court upholds the verdict.
Rival protesters at a central Dhaka intersection erupted in jubilation as news of Sayedee's sentence filtered through. "We've been waiting for this day for the last four decades," a protester told Somoy TV.
There was no immediate reaction from Jamaat to the verdict, but the party has enforced a nationwide strike demanding a halt to the trials.
The cases against eight more Jamaat leaders are still being heard.
Earlier this month, the tribunal a local court with no international oversight sentenced Jamaat's assistant secretary general Abdul Quader Molla to life imprisonment.
While angering Jamaat supporters, that verdict also enraged secular protesters, tens of thousands of whom have since poured onto the Shahbag intersection in central Dhaka to demand the execution of Jamaat leaders.
In January the tribunal handed down its first verdict when it sentenced fugitive Muslim TV preacher Maolana Abul Kalam Azad to death.
The tribunal has been tainted by controversies and allegations that it is targeting only the opposition with trumped-up charges. Rights groups say its legal procedures fall short of international standards.
A judge presiding over Sayedee's case resigned after leaked internet calls showed there was collusion between him and the prosecution. A key defence witness was also abducted from the court premises by policemen, allege Sayedee's lawyers.
The government rejects the accusations, saying the tribunal is independent and the trials are fair and necessary to heal the wounds of the war that it says killed three million people.
It accuses Jamaat leaders of being part of pro-Pakistani militias blamed for much of the 1971 carnage.
Independent estimates put the war toll much lower, between 300,000 and 500,000.