After celebrating 21 years as an active chapter of Theta Kappa Pi at Penn State University, the Alpha chapter made a historic decision to accept membership in Phi Mu National Fraternity. On September 18, 2005, the executive board of the Alpha chapter of Theta Kappa Pi, the current members of the Beta Mu chapter of Phi Mu, and four representatives of the Phi Mu National Organization met at Penn State's University Park campus to discuss a possible merger of the two organizations. Concluding the presentation, 67 members of Theta Kappa Pi were offered a blanket bid to join Phi Mu. On Tuesday, September 20, 2005, 65 of the 67 Theta Kappa Pi members accepted this invitation. A ribboning ceremony was later conducted for the new members of Phi Mu on September 29, 2005. The new members then participated in the national Phi Mu new member program under the direction of full-time Phi Mu leadership consultant, Allie Kearns.
The decision to merge the two organizations was the result of many different factors. At the time, Phi Mu had struggled with a lack of interested potential members, however, possessed the national backing of a National Panhellenic Conference sorority. Meanwhile, Theta Kappa Pi had the membership numbers, however, sought the legitimacy and national backing. The decision to merge offered the two organizations a quick solution to these issues.