We selected a Eu(3+)-containing tungstogermanate [(CH(3))(4)N](2.5)H(7.5)[Eu(GeW(11)O(39))(H(2)O)(2)](2)·4.5H(2)O (EuGeW) as a molecular dyad combining fluorescence and electroactivity components within the same framework and studied its electroswitchable fluorescence in solution and in the thin-film, which can be reversibly switched by electrochemical stimulation.