The title compound, C15H11FN4OS, crystallizes with three independent molecules (A, B and C) in the asymmetric unit. The dihedral angles between the nine-membered 5-fluoroindolin-2-one ring system and the benzene ring are 22.14 (11), 12.56 (11) and 3.70 (11)° in molecules A, B and C, respectively. In all three molecules, intramolecular cyclic N—H⋯O and C—H⋯S hydrogen-bonding interactions [graph set S(6)] are present in the N—N—C—N chain between the ring systems. In the crystal, the A molecules form centrosymmetric cyclic dimers through intermolecular N—H⋯O hydrogen bonds, which are linked into a supramolecular chain along [100] via C—H⋯F interactions; each type of hydrogen bond has graph set graph set R
2
2(8). A similar chain stabilised by similar interactions and also along [100] but, comprising alternating molecules of B and C is found. The latter chains are connected via C—H⋯S interactions, forming a layer with a zigzag topology parallel to (001).