A series of π-conjugated compounds ending with 9,9-diethyl-1-phenyl-1,9-dihydrofluoreno2,3- d imidazole were conveniently synthesized by condensation of the key intermediate 9,9-diethyl-N 2 -phenyl-9H-fluorene-2,3-diamine with the corresponding symmetric aryl phthalaldehydes under very mild conditions. The structures of these compounds were confirmed by 1 H NMR, 13 C NMR, and HRMS. Their UV-Vis spectroscopy data, fluorescent spectroscopy data, and further details of the electronic properties from cyclic voltammetry measurements and theoretical calculations were studied. Most compounds possess good fluorescence-emitting ability with quantum yield of fluorescence values in the region of 0.36–0.92 and display emission within 449–513 nm depending on the molecular nature.