When the Gandhis received tax notices in the case, Sonia Gandhi had called it political witch-hunt.
Sonia Gandhi and Rahul Gandhi have to appear in a Delhi court to face allegations that they illegally acquired property worth Rs 5,000 crore belonging to the National Herald newspaper.
The Delhi High Court on Monday dismissed the petition of the two top Congress leaders asking that a lower court summons to them be cancelled.
"We will move the Supreme Court tomorrow morning. It is a vacuous case," said Congress' Abhishek Manu Singhvi, who appeared for the Gandhis.
There were chances that the two leaders might have to appear in court as early as Tuesday, but the Congress legal team said they will ask for an alternative date. The party fears that a court appearance will blunt its attack on the government in the middle of the Parliament session.
Rahul Gandhi is expected to visit flood-hit Tamil Nadu on Tuesday.
The case is based on BJP leader Subramanian Swamy's allegation of cheating and criminal breach of trust against senior Congress leaders including the Gandhis.
Mr Swamy alleges that the Congress leaders gave a Rs 90 crore loan out of tax exempted money to National Herald and broke the law to acquire it for just Rs 50 lakh with the aim of grabbing its properties in Delhi worth thousands of crores.
The High Court questioned why the party gave an interest-free loan to National Herald and called it a case of siphoning of funds. To the Congress argument that Mr Swamy had no right to complain, the court said: "The freedom of a citizen to move against the corrupt can't be restricted."
Mr Swamy said: "It is an open and shut case."
The newspaper set up in 1938 by Jawaharlal Nehru played a prominent role in promoting nationalist sentiment before India's independence in 1947. The publication was dogged by bad management, poor circulation and falling revenue, and Sonia Gandhi decided to close it down in 2008.
The Congress maintains that they gave a loan of Rs 90 crore to the paper because it was nationalistic and it suited the objectives of the party.
When the Gandhis had earlier received tax notices in the case, Sonia Gandhi had called it political witch-hunt.