Spinach-based photo-catalyst for selective plating on polyimide-based substrates for micro-patterning circuitry

•For the first time copper microtracks are photo-catalysed by a plant extract.•Spinach extract is used as a catalyser for the synthesis of Ag NPs on polyimides.•The photo-patterning reaction is accelerated by an order of magnitude.•Highly conductive, photo-induced selective electroless copper plating is obtained.•A simple extraction method of chlorophyll-A from spinach at 120mg/L is developed.