Preheat oven to 350 degrees F (175 degrees C). Grease a 9x9 inch square pan. In the microwave or in a metal bowl over a pan of simmering water, melt chocolate chips, stirring frequently until smooth. Set aside.
Cream together the shortening and sugar until smooth. Beat in the eggs one at a time then stir in the vanilla. Combine the flour, baking powder, salt and cinnamon; blend into the creamed mixture. Divide batter into separate bowls. Mix the melted chocolate into one half and the drained crushed pineapple to the other. Spread the chocolate batter evenly into the prepared pan, then spread the pineapple batter over the top of that.
Bake for 30 to 35 minutes in the preheated oven. Cool in the pan on a wire rack.