The rational selection of a character, size and placement of substituents in the dye is vital for obtaining their desirable properties. It has been shown that the orderly change of electron-donating/withdrawing substituents in fluorophores affects non-radiative rate constants in a linear way. On the othre hand, it has been demonstrated that the regioisomers of anthracene exhibit the AIE behaviour in two among five investigated derivatives, whereas the triphenylamine-decorated benzo[i]dithiophenephenazines can be transformed from the ACQ to AIE form via modification of their crystal packing caused by relocation of electron-donating substituents -increase of FQY by more than 15%. Scheme 1. Structure of investigated compounds