Presiding judge Justice Kwaku Ackah-Boafo, dismissed the application on procedural grounds and lack of merit.
The suit against Thaddeus Sory was thrown out by the Accra High Court.
On July 25, 2017, Mrs Osei sued Mr Opoku-Agyemang for defamation and professional misconduct in the court.
That was after the leakage of a 27-page petition to the Presidency calling for her impeachment, said to be from some workers of the EC represented by Mr Opoku-Agyemang.
Conflict of interest
However, Mr Opoku-Agyemang has filed an application seeking an order from the court to restrain Mr Sory and his law firm, Sory @ Law, from representing Mrs Osei in the matter.
It also wants the court to dismiss the writ filed by Mr Sory on behalf of Mrs Osei in the defamation case.
Lawyer for Mr Opoku-Agyemang, Mr Julius Opoku Adjei, told the court that Mr Sory must not be allowed to represent the EC boss in the defamation case because of conflict of interest.
The defamation case, he said, was borne out of the petition seeking to impeach Mrs Osei as such Mr Sory, who is also the lawyer for the EC, could not represent the EC boss.
Counsel argued that the petitioners, in seeking the impeachment of Mrs Osei, were fighting in the interest of the EC and, therefore, Mr Sory could not protect the interest of the EC by representing its boss.
He further contended that the manner in which the EC engaged the services of Mr Sory and his law firm was also a part of the subject matter of the petition.