Space time block codes (STBCs) have been studied to exploit the spatial and temporal diversities in wireless systems. Orthogonal space time polarization block codes (OSTPBCs) designed using the quaternion algebra promise gains in terms of higher data rates, diversity and spectral efficiency. In this context, quaternion modulation has been proposed using the dual-polarized antennas to generate efficient selection of the polarization and optimal decoding at the receiver end. In this paper, the quaternion modulation technique has been evaluated considering the quaternionic channel using the dual-polarized antennas. The results show promising diversity gains with benefits in terms of spectral efficiency and data rates. An extension of this scheme for higher number of symbols and higher dual-polarized antenna dimensions has also been presented. The proposal includes linear decoupled decoding of the quaternion orthogonal codes (QODs) at the receiver end where the complexity stays independent of the number of transmitted symbols. The design of the quaternion modulation using the quaternionic channel fully exploits the polarization diversity in addition to unfolding its applicability for future massive multiple-input multiple-output (MIMO) wireless systems.