Anisotropy of optical transitions of monosolvate and disolvate species of chlorophyll “a” (Chl) and protochlorophyll “ a ” (PChl) have been investigated using fluorescence polarization (FP), circular dichroism (CD) and magnetic circular dichroism (MCD). The QX(o-o) transition of monosolvate species is found at 621-630 nm, while the QX(o-o) transition of Chl disolvate species at 639-642 nm. Therefore, previously accepted assignment of the Chl QX(o-o) transition is not correct. The longest wavelength transition of PChl is assigned to QX(o-o).