BJP national general secretary Ram Madhav had issued the invite when he was in Dhaka in October. Not just party level proximity, the two governments appear to be stepping closer than ever before.
"Our relationship has reached a new constructive high," said Mr Quader who is in Kolkata to mark the 46th anniversary of the liberation of Bangladesh on 16 December 1971.
"Whatever government comes in Delhi, we will have a relationship. After all, India stood by us in our worst time," he said.
"But whether it was the 68-year-old Indira-Mujib border pact or the enclave exchange or the dispute over international waters, the UPA tried to resolve them but Mr Narendra Modi made it happen. What's wrong with appreciating that?" Mr Quader said.
Because the disputes were dragging, there was a "wall of doubt", the Awami League chief said. But that was broken when Mr Modi delivered. "We started believing India can be depended upon."
"No relationship is without self-interest. Even you have national interest. So do we," Mr Quader said.
BNP chief and former Prime Minister Begum Khaleda Zia met India's external affairs minister Sushma Swaraj in Dhaka in October. General elections were discussed and Ms Swaraj is reported to have encouraged "participatory" elections. BNP had boycotted general elections in 2014.
In June 2015, Begum Zia had met PM Modi in Dhaka and complained of "the lack of democracy" in Bangladesh.
Traditionally, the Awami League is seen as a pro-India party and Sheikh Hasina has delivered on cracking down on insurgent groups and anti-India elements sheltering in Bangladesh. BNP has often labeled Awami League leaders as "India's agents".
Though the Bangladesh ruling party was deeply disappointed with the Modi government's response to the Rohingya crisis that erupted in August, it has never publicly said so.
As Rohingyas streamed in from Myanmar into Bangladesh, PM Modi visited Myanmar leader Aung Sang Suu Kyi in Yangon but did not say a word about the Rohingya exodus into Bangladesh.