Dipole moments of 2,4,5-trimethylbenzaldehyde (TMB) isolated in a durene host crystal have been reported to be 1. 65 ± 0. 09D (difference between the ground state and the lowest singlet) and 1. 05 ± 0. 06D (difference between the ground state and triplet excited states). TMB has been identified as one of the major volatile constituent present in the leave extracts of Eryngium foetidum L. Based on the phosphorescence excitation and Stark spectral data, it has been observed that a change in temperature and electric field causes a change in the dipole moment of the compound.