The court said the case against Nirupam will continue.
Justice R K Gauba passed two separate verdicts on the two leaders plea.
In her plea, Irani had sought quashing of the summons issued to her by a trial court on June 6, 2014. She had also sought quashing of the complaint filed by Nirupam.
Nirupam had challenged a magisterial court's March 11, 2013 order summoning him in Irani's defamation complaint against him. He had also sought quashing of the January 1, 2013 complaint filed by Irani.
(With inputs from agencies.)