Place sliced bananas in a large pot or Dutch oven over medium-high heat and top with sugar, pineapple (and juices), sugar, coconut and lemon juice, and bring to a boil.
Reduce heat to medium-low and, stirring frequently, cook until mixture is thickened and has reduced down. Banana slices will break down into pieces.
Mixture is ready when it coats the back of a spoon; remove from heat and transfer to glass jars. Let cool, then refrigerate until ready to use.
