The reactants of the dark reactions of photosynthesis are:

* Carbon dioxide (CO2): This is the primary source of carbon for building sugars.

* ATP (adenosine triphosphate): This is the energy currency of the cell, produced during the light-dependent reactions.

* NADPH (nicotinamide adenine dinucleotide phosphate): This is a reducing agent, carrying high-energy electrons produced during the light-dependent reactions.

These reactants are used to convert carbon dioxide into glucose, the primary product of photosynthesis.