An easy-to-use phosphate triggered zinc-azophenine complex assisted metal extrusion assay: A diagnostic approach for chronic kidney disease and in silico docking studies

•Azophenine derived Zn(II) complex, CN-1·Zn2+ is synthesized by FeCl3 mediated CN bond fusion pathway in neat condition.•CN-1·Zn2+ can selectively detect H2PO4- (LOD of 67.9 ppb) with distinct naked eye chromogenic transitions.•H2PO4- detection ability from serum specimen makes it potential analytical tool for monitoring CKD.•Concentration dependent chromogenic detection of H2PO4- analyzed by Smartphone assisted RGB APP is particularly important in the developing countries.•Investigational and in silico docking studies exhibit prominent non-intercalative DNA binding activity of CN-1·Zn2+.