The rally is part of a flurry of action from Maryland churches and civil rights groups seeking to memorialize Martin, the 17-year-old who was unarmed when he was shot and killed Feb. 26 in Sanford, Fla., on Feb. 26 by neighborhood watch volunteer George Zimmerman.
"It's a sad, tragic situation," said Baltimore NAACP President Tessa Hill-Aston. "You got a young boy trying to walk away from somebody, drinking a soda and eating candy like any other young person."
Hill-Aston said that beyond expressing sadness and anger, she hoped to be constructive by focusing on proper methods of neighborhood patrol.
"You're supposed to call for police backup," she said. "You do not touch someone. That could have been anyone's child."
The National Association for the Advancement of Colored People will be joined by the Maryland Southern Christian Leadership Council and the Baltimore National Action Network in organizing the 5 p.m. rally at Pratt and Light streets. That will follow a Sunday afternoon prayer vigil at Rising Sun First Baptist Church in Gwynn Oak.
Among others intervening locally are Jamal Bryant, pastor of the Empowerment Temple, a large church in Baltimore, and former Baltimore Mayor Kurt L. Schmoke, dean of the Howard University School of Law. Bowie State University leaders also plan to discuss the situation during a campus "Peace Week" starting Monday.
They have joined a growing network of civil rights leaders and others to raise questions — and, in some cases, voice outrage — about potential racism in the teen's death. Martin was black.
The Miami Herald reported that Bryant said at a recent rally, "This is a wake-up call for the state of Florida!"
Bryant will preach about Martin at 9:30 and 11:30 services in Baltimore on Sunday before he travels to Florida for a Monday event.
The Florida protest is planned for a Sanford City Council meeting, according to The Herald. Black leaders have said they will rally 1,000 or more people if charges are not filed in the case. A Seminole County, Fla., grand jury, the FBI and the U.S. Department of Justice are investigating, according to the NAACP.
Schmoke told NBC4 in Washington that the Howard University community wants to help.
"We simply wanted to offer our condolences, and then our offer of assistance to the lawyers," Schmoke told the station. "We could help with not only the investigation but, more importantly, looking at the law."
Benjamin Todd Jealous, national president of the NAACP, joined others in demanding that Sanford Police Chief Bill Lee Jr. be replaced. The Orlando Sentinel reported Saturday that Lee had temporarily stepped down.
"My role as the leader of this agency has become a distraction from the investigation," Lee said in a statement. "It is apparent that my involvement in this matter is overshadowing the process.
"Therefore, I have come to the decision that I must temporarily relieve myself from the position as police chief for the city of Sanford," he continued. "I do this in the hopes of restoring some semblance of calm to a city which has been in turmoil for several weeks."
Jealous said in a statement: "The NAACP's No. 1 concern in this case remains securing the arrest, prosecution and conviction of George Zimmerman. We are cautiously pleased that Chief Lee has stepped aside for his failure to assure Mr. Zimmerman was arrested.
"Any chief who would so allow his officers to so mishandle a situation like this has no place in law enforcement. At the end of this investigation it will be clear that his temporary removal should be made permanent."