The molecule of the title compound, C(17)H(17)N(5)O(2)S, consists of three pi systems, viz. two aromatic rings and the triazene moiety, which are mutually deconjugated although coplanar. The n-butyl chain is roughly perpendicular to the molecular plane, with the terminal methylene and methyl groups disordered between two equally populated positions. The molecules in the crystal associate in an antiparallel fashion, forming dimers across the centre of symmetry, the principal intradimer interaction being stacking of the pi-electron portions of the molecules.