The first Cu-II-induced cyclic guanylation of thiourea anthraquinone (1), exhibiting high selectivity towards Cu-II over other competitive cations in aspects of fluorometric and colorimetric chemodosimetry, is reported. Moreover, mesoporous silica-immobilized anthraquinone (MSIA) is also fabricated and shows Cu2+ ion selectivity with respect to a color change from red to yellow.