We investigate an enhancement of the orientation of OCS molecules by irradiating them with a near IR (omega) ultrashort laser pulse for alignment followed by another ultrashort laser pulse for orientation, which is synthesized by a phase-locked coherent superposition of the near IR laser pulse and its second harmonic (2 omega). On the basis of the asymmetry in the ejection direction of S3+ fragment ions generated by the Coulomb explosion of multiply charged OCS, we show that the extent of the orientation of OCS is significantly enhanced when the delay between the alignment pulse and the orientation pulse is a quarter or three quarters of the rotational period. The recorded enhanced orientation was interpreted well by a numerical simulation of the temporal evolution of a rotational wave packet prepared by the alignment and orientation pulses. (C) 2018 Elsevier B.V. All rights reserved.