Time-resolvedESR spectra have been observed for the phosphorescent triplet states of 2,2′-biquinoline (BQ), 2,2′-biquinolinium (BQH+) and [Zn(bq)]2+ in ethanol at 77 K. The analysis of the spectra showed that the sublevel initially populated by intersystem crossing is mainly Tx in both BQ and BQH+, while it is mainly Ty in [Zn(bq)]2+ (the x axis is close to the long axis of the molecule and y is in