The Theta Xi Fraternity Chapter House at Rensselaer Polytechnic Institute is listed on the National Register of Historic Places.

Debates were common and encouraged at Sigma Delta meetings; however, on the evening of October 30, 1863, George Brainerd tendered his resignation to the society.

[1] On March 12, 1864, voting took place for members of a new organization, and on April 1, a committee consisting of Waite, Buel, Brainerd, and Packard began preparing a new constitution.

[1] The Theta Xi Fraternity Chapter House at Rensselaer Polytechnic Institute was listed on the National Register of Historic Places in 2013.

In honor of this occasion, the National Convention was held in Troy, New York to commemorate the founding of Theta Xi.

[5][6][7] The Purpose of Theta Xi is to provide a college home environment for its active members in which fellowship and alumni guidance lead to wholesome mental, moral, physical, and spiritual growth.

To that end Theta Xi actively supports and augments college and community efforts to make individual members more mature and chapter groups more useful units of society.

Through its alumni and undergraduate leadership Theta Xi endeavors to assist each member to develop: ONE, intellectual curiosity that assures the highest scholarship rating consistent with his ability; TWO, habits that lead to better mental and physical health; THREE, sincerity in his association with others and confidence in himself; FOUR, responsibility to chapter, college, community, and country; FIVE, leadership that comes from practicing the principles of democratic self-government; SIX, interests and activities outside regular scholastic studies that employ spare time to advantage; SEVEN, spiritual understanding that provides a reservoir of strength to draw upon when faced with conditions beyond comprehension.

[8] At the 111th Anniversary Convention held on August 12, 1974 Theta Xi announced its adoption of the fight against Multiple Sclerosis as its National Service Project.

On June 20, 1986 Theta Xi was named the Outstanding Volunteer Organization for 1985-86 by the National Multiple Sclerosis Society.