Answer
Both $OCS$ and $CS_{2}$ are linear molecules. The two bond moments in $CS_{2}$ are equal in magnitude, but they point in opposite directions, so the resultant dipole moment of $CS_{2}$ is zero. In contrast, the two dipole moments in $OCS$ are not equal in magnitude, even though they point in opposite directions, so the resultant dipole moment of $OCS$ is not zero. Therefore, the molecule $OCS$ will have a higher dipole moment than $CS_{2}$.
Work Step by Step
Both $OCS$ and $CS_{2}$ are linear molecules. The two bond moments in $CS_{2}$ are equal in magnitude, but they point in opposite directions, so the resultant dipole moment of $CS_{2}$ is zero. In contrast, the two dipole moments in $OCS$ are not equal in magnitude, even though they point in opposite directions, so the resultant dipole moment of $OCS$ is not zero. Therefore, the molecule $OCS$ will have a higher dipole moment than $CS_{2}$.
