Bulk superconductivity and Pauli paramagnetism in nearly stoichiometric <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>CuCo</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">S</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math>

It has long remained elusive whether ${\mathrm{CuCo}}_{2}{\mathrm{S}}_{4}$ thiospinel shows bulk superconductivity (SC). Here we clarify the issue by studying samples of sulfur-deficient ${\mathrm{CuCo}}_{2}{\mathrm{S}}_{3.7}$ and sulfurized ${\mathrm{CuCo}}_{2}{\mathrm{S}}_{4}$. The sample a smaller lattice constant $a=9.454$ \AA{}, it is not superconducting down to 1.8 K. After full sulfurization, $a$ axis phase increases 9.475 becomes nearly stoichiometric ${\mathrm{CuCo}}_{2}{\mathrm{S}}_{4}$, although secondary slightly Cu-doped ${\mathrm{CoS}}_{2}$ forms. Bulk SC at 4.2 K Pauli paramagnetism have been demonstrated for measurements electrical resistivity, magnetic susceptibility, specific heat.