Members of the Isley Brothers are submerged in a nasty lawsuit over trademark rights to the legendary name.

According to Billboard, Rudolph Isley sued his brother, Ronald Isley, who wanted to legally acquire a federal trademark registration for “The Isley Brothers” name.

Rudolph’s lawyers argued that the judge should throw out the case, considering Ronald left the group.

But Rudolph claimed he was still operating as a member of The Isley Brothers despite not performing with them since the late ’80s, arguing they should share the name.

Ultimately, U.S. District Judge Thomas M. Durkin denied Ronald’s request to dismiss the lawsuit, supporting his decision with the NYC doo-wop group Vito & the Salutations lawsuit.

“Plaintiff’s contention is that when he ceased performing, he did not leave the group, but instead took on the sort of continuing managerial role that creates a continuing ownership right in the mark,” the judge wrote. 

There have been instances where judges ruled a member of a music group didn’t possess the right to ownership of the mark because they lost it after leaving the group and disassociated themselves.

But Judge Durkin ruled that Rudolph’s lawsuit could potentially rule in his favor since he maintained a “behind-the-scenes” role.

In one instance, Rudolph argued he assisted in the 2018 multi-million dollar publishing deal, where their song, “Shout,” was used for a commercial during the Super Bowl. 

In addition to jointly owning the trademark rights to “The Isley Brothers” name, Rudolph wants the court to force Ronald to split revenue obtained from the trademark with him and explain how he “exploited” it.

In a statement to the outlet, Brian D., Rudolph’s lawyer, said his client was grateful for Judge Durkin’s ruling to deny “his brother’s motion to dismiss his complaint” and “looks forward to recognition of his rights as a 50% owner in the name ‘The Isley Brothers,’ the iconic name of the band that he formed in 1954 with his two brothers.”

O’Kelly Isley was their third brother, who died in 1986.