Seven ionic liquids (ILs) based on tetrabutylammonium cation [N+4444] and inorganic anions were tested for their applications in a solar cooker. Thermophysical characteristics like melting point, density, heat of fusion, heat of solid - solid transitions, specific heat capacity and thermal conductivity were used to determine the efficiency of ILs used as phase change materials (PCMs) in solar thermal applications. A delay time of two hours was observed on an average in achieving the highest temperatures. A majority of the ILs extended the time required for achieving ambient temperature to a tune of around four hours. The ILs containing bromide, iodate and nitrate proved to be more efficient than the thiocyanate, bromate and hexafluorophosphate moieties.