American singer, Rudolph Isley, 83, has filed a lawsuit against his 81-year-old brother Ronald Isley over trademarks to the legendary musical group’s profits.

Rudolph in legal documents obtained by TMZ said that Ronald made business transactions without his knowledge that potentially cost him money.

According to the suit, Rudolph told the court that Ronald successfully applied for the trademark to the name The Isley Brothers last summer, and has since collected all of the profits.

Rudolph said in legal docs that he and his younger brother had agreed to evenly split the band’s profits, claiming they’ve each had 50% ownership in the band since the death of their brother and bandmate O’Kelly who died from a heart attack in 1986.

According to the documents, Rudolph claims his brother Ronald violated the arrangement they agreed upon when he obtained the use of the name for ‘visual recordings and audiovisual recordings featuring music and animation’ last August after applying in November 2021.

Rudolph said that that Ronald needed his authorization to obtain the trademark, but did not contact him about the deal ahead of time.

Rudolph said that for decades, he and Ronald evenly divided the profits – including multimillion dollar publishing arrangements – prior to recent developments.

Rudolph has requested the judge in the case to audit Ronald’s earnings since the change, and have him reimburse him for half of the money.

He is also requesting the judge to declare :The Isley Brother’ trademark is jointly owned by him and his brother

The Cincinnati, Ohio-based group initially started out as a quartet with brother Vernon Isley, who died at the age of 13 in a 1955 car accident.

They continued with Ronald as lead singer and Rudolph and O’Kelly as backup singers.

The group was inducted into the Rock & Roll Hall of Fame in 1992.