They were part of a group of six workers who were detained under the Terrorism (Suppression of Financing) Act in May.
They were charged under the Internal Security Act (ISA) on August 30 had pleaded guilty on Tuesday.
Mamun Leakot Ali, 30, was sentenced to two and a half years' jail, while Zzaman Daulat, 34, was sentenced to two years' jail.
The workers were accused of funding a group called the Islamic State in Bangladesh (ISB) and were collecting or providing money to fund terrorist attacks back home, The Strait Times reported.
Authorities also found in their possession a list of targets and bomb-making manuals.
Mamun was the group's deputy leader, while Zzaman was in the group's security council.
Mamun and Zzaman had initially claimed trial. The other four pleaded guilty and were jailed between two and five years last month.
Addressing the court, their lawyer said both men were deeply apologetic to the people of Singapore for causing fear and harm through their actions.
Pleading for a more lenient sentence, their lawyer added that both men had committed their crimes in a moment of foolishness, and were now deeply ashamed for bringing down the repute of Islam and other Muslims.
Their lawyer said: "He is a Muslim, he believes in Islam, and he realises that these are not teachings of his religion... It is not the way of Islam."
The goal of ISB was to topple the Bangladesh government, set up an Islamic state and bring it under the self-declared caliphate of the Islamic State (IS) terrorist group.
Two other ISB men in Singapore were also detained in April -- they have been given two-year detention orders under the ISA and have not faced formal charges in court, The Strait Times reported.
They were led by ringleader Rahman Mizanur, 31, who got the heaviest sentence of five years' jail.
Miah Rubel, 26, and Md Jabath Kysar Haje Norul Islam Sowdagar, 31, acted as the group's treasurers, and received two and a half years' jail.
Sohel Hawlader Ismail Hawlader, 29, donated $300 to the cause, and was given two years' jail.
