The members will be taken to New Delhi by Rajdhani Express on Wednesday.
"The party has decided to take the family members of our activists, who were killed in widespread political violence unleashed by the Trinamool Congress, to attend Modiji's oath-taking ceremony at the Rashtrapati Bhavan. We have shortlisted 70 family members so far," BJP state Secretary Tushar Kanti Ghosh told .
"One or two family members of each of the deceased activists have been shortlisted. Relatives of approximately 50 of our deceased activists are going. They are scheduled to come back on May 31," he said.
Relatives of all three BJP activists Sishupal Sahish, Trilochan Mahato and Dulal Kumar who were killed and hanged from tress in Bengal's Purulia district are among those going to Delhi.
The invitation to these families is being seen as a message to West Bengal Chief Minister and Trinamool Congress chief Mamata Banerjee ahead of Assembly elections scheduled in 2021.
Among the special guests at the event will be leaders from BIMSTEC (Bay of Bengal Initiative for Multi-Sectoral Technical and Economic Cooperation) countries and a host of celebrities and politic.
During the Lok Sabha election campaign, Modi and BJP President Amit Shah repeatedly highlighted the issue of violence directed at the party in West Bengal.
The BJP won 303 seats on its own in the Lok Sabha elections, and in West Bengal it took its tally to 18 from two in 2014.
Leaders from BIMSTEC countries as well as Kyrgyz President Sooronbay Jeenbekov and Mauritian Prime Minister Pravind Kumar Jugnauth have confirmed their participation at Thursday's event.
( With inputs from IANS )