The phone call to Sonia Gandhi and meeting with Patel happened late on Tuesday night.
Following another round of talks today (Wednesday), Thackeray said: "The discussions with the Congress are proceeding in the right directions. You will be informed of everything at the right time."
State Congress chief Balasaheb Thorat also said that Wednesday's meeting was a preliminary one and more would be discussed after the Congress and Nationalist Congress Party talk among themselves.
Thackeray was joined by senior Sena leaders including Subhash Desai, Eknath Shinde while Thorat was accompanied by former state Congress chief Manikrao Thakre and former Chief Minister Ashok Chavan.
The Congress-NCP have also made five-member committees on each side to chalk out the power-sharing formula and a Common Minimum Programme on the basis of which they plan to join hands with the Sena.
On Monday, the Sena made the first formal approach to the Congress when Thackeray called up Sonia Gandhi to solicit her support for forming a government as it (Sena) was the second largest party.
A bit wary, the Congress-NCP combine has adopted a cautious approach by not jumping at the Sena's proposal, but decided to discuss its ramifications among themselves.
An anxious Sena, which was hoping for letters of support from both, was disappointed when the communication did not come before the expected time on Monday evening.
A delegation comprising Aditya Thackeray, which waited for the support letters at Raj Bhavan, sought two more days from Governor B.S. Koshyari, which was refused.
The Shiv Sena leaders returned after staking their claim to form the government, but without being able to prove the support from the Congress and the NCP.
The Congress-NCP announced on Tuesday that they will first discuss the proposed alliance with the Sena in detail and then talk with the party on the possibility of forming a government with a CMP.
( With inputs from IANS )