1. An anthracene derivative of the formula: ##STR10## wherein R.sup.1 and R.sup.2 are independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a hydroxyl group; R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, or a group of the formula: ##STR11## wherein R.sup.1 and R.sup.2 are as defined above, provided that at least one of R.sup.3 through R.sup.6 is the group of the formula [II], and the group of the formula [II] in number of 3 cannot be positioned at the 1, 8 and 9 positions of the anthracene ring at the same time.