Jul 02, 2014 06:34 AM EDT By Staff Reporter, UniversityHerald Reporter

Juniors Paul Gerlich and Erin Furleigh, two Iowa State University students, have filed a federal lawsuit after the school's trademark licensing office prohibited a pro-marijuana group from using the "Cy the Cardinal" mascot logo on its T-shirts.

The lawsuit, filed in the U.S. District Court for the Southern District of Iowa, claims that forbidding the Cy logo on T-shirts made by the school chapter of NORML (the National Organization for the Reform of Marijuana Laws) is a clear violation of students' First Amendment rights, USA Today reports.

Gerlich and Furleigh are president and vice-president of the student group.

Steven Leath (ISU's president), Warren Madden (the senior vice president of business and financial affairs) and Thomas Hill (the senior vice president for student affairs as defendants) have been named as defendants.

In 2012, ISU officials barred the Cy the Cardinal logo on NORML's T-shirts after photos triggered complaints from legislators. The political leaders said that using the logos gives an impression that the school is supporting marijuana legalization.

In January 2013, the school updated its trademark policy banning mascot use on items related to "drugs and drug paraphernalia." Since the policy change, T-shirt designs featuring the ISU initials and a cannabis leaf have been rejected, according to the lawsuit.

The students claimed that the ban "hindered NORML ISU from challenging the orthodoxy that marijuana-use should be prohibited."

"By policy and practice, however, ISU unlawfully restricts its students' and faculty's constitutional right to free expression."

The lawsuit said that only two states have legalized marijuana for recreational use and 21 of them authorised pot for medical purpose.

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