Sensor activity and logic behaviour of PET based dihydroimidazonaphthalimide diester

► Novel naphthalimide derivative is designed as PET based sensor according the “fluorophore-spacer-receptor” model. ► The sensor naphthalimide efficiently detects protons, Bi3+ and Fe3+ ions. ► The ability of the system to act as multi-functional logic device is demonstrated. ► The molecule acts as a molecular pH metre, digital comparator and half-adder. ► The novel comparator serves as a fundamental element for control of pH windows.