In the mononuclear title complex, [CuI(C6H8N2S)(C18H15P)2], the CuI ion is in a slightly distorted tetra­hedral coordination geometry formed by two P atoms from two triphenyl­phosphane ligands, one S atom from a 4,6-dimethyl­pyrimidine-2(1H)-thione ligand and one iodide ion. There is an intra­molecular N—H⋯I hydrogen bond. In the crystal, π–π stacking inter­actions [centroid–centroid distance = 3.594 (1) Å] are observed.

In the title compound, C19H18NO+·I−·0.5I2, the I2 mol­ecule lies on a crystallographic center of symmetry and the cation is essentially planar and in an E configuration. The dihedral angle between the quinolinium and benzene ring systems is 4.06 (10)°. In the crystal structure, the cations are packed in an anti­parallel fashion along the a axis and weak C—H⋯O and C—H⋯I inter­actions link the components of the structure into a three‐dimensional network. Weak C—H⋯π inter­actions are also present.