Ruthenium(II) complex-based chemosensors for highly sensitive and selective sequential recognition of copper ion and cyanide

•Two new 2-hydroxyphenyl imidazo appended ruthenium complexes (RuL1 and RuL2) were synthesized and characterized.•Sensing ability of RuL1 and RuL2 for Cu2+ were successfully carried out in aqueous buffered solution (20mM HEPES, pH=7.2) containing 1% (v/v) CH3CN.•The resulting RuL1–Cu2+, RuL2–Cu2+, and [Ru(bpy)2HPIP]2+–Cu2+ ensembles acted as efficient fluorescent chemosensors for CN−.•Detection limits for CN− were down to submicromolar concentrations (0.36μM for RuL1–Cu2+, 0.87μM for RuL2–Cu2+, and 0.62μM for [Ru(bpy)2HPIP]2+–Cu2+).