Rudolph Isley sues brother Ronald over ‘The Isley Brothers’ trademark

Rudolph Isley slapped his younger brother Ronald Isley with a lawsuit over trademarks to their legendary music group’s name, The Isley Brothers.

In legal documents obtained by TMZ, the 83-year-old alleged that Ronald made business transactions without his knowledge which ultimately ended up costing him money.

Rudolph insists that his brother’s application to trademark the name The Isley Brothers was approved last summer and that he’s been cashing in on profits ever since.

In the suit, Rudolph says he and his brother had agreed to evenly split the band’s profits following the sudden death of their brother and bandmate O’Kelly, who died from a heart attack in 1986.

The suit alleges that Ronald violated the pair’s agreement and obtained the use of the band’s name for “visual recordings and audiovisual recordings featuring music and animation.”

The Ohio native maintains that he was not consulted on the decision.

Rudolph is requesting to be reimbursed for half of the earnings and is asking the judge to reinstate his 50 percent share in the Grammy-winning band’s revenue.

The band, which was formed in Cincinnati back in the 1950s, initially started out as a quartet with brothers Rudolph, Ronald, O’Kelly, and Vernon — who died aged 13 in a car accident.

The brothers went on to perform together as a trio, with Ronald becoming the lead singer.

The band’s successful music catalog saw them find mega-stardom with hits like 1959’s “Shout,” 1962’s “Twist and Shout,” 1966’s “This Old Heart of Mine (Is Weak for You),” 1973’s “That Lady,” and the hit 1975 track “Fight the Power.”

The brothers became Grammy winners in 1970 after scooping the award for Best R&B Vocal Performance by a Duo or Group for their track, “It’s Your Thing.”

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

More recently, they were given a Grammy Lifetime Achievement Award in 2014.