The shrine of Hilal ibn Ali is an incredible piece of architecture but yet I cannot find any info online about who built it and when!
The construction of this building goes back to the Safavid period (1501-1736) and it has been renovated several times thus far. The interiors of the building are decorated with watercolor paintings. There is a marble plate in the northern balcony just above the entrance which is inscribed with some information about the construction of this monument. There is also a script carved on the wooden front door which provides some information about the person who endowed the door to the holy shrine during the Qajar period, in 1849. Kashancht.ir