Strong spin-orbit coupling often leads to exotic properties in otherwise a well understood pool of 'paramagnetic' heavy ion oxides. For a 5d4 system a J=0 total angular momentum ground state should be realised in a jj coupling scheme, which has not been observed till today. This is due to a subtle balance between electronic repulsion, crystal field (CF) and SOC, which makes the J=0 state a fragile one and also because in some cases singlet-triplet excitations of pseudospins may be at play. These excitations give rise to tiny magnetic moments which owing to exchange interactions on geometrically frustrated lattices may give rise to spin-orbital liquid state. We propose to probe with muSR such frustrated 5d4 iridate compounds having variations in the crystal field, based on the local Iridium coordination and overall crystal lattice.