Preheat oven to 350 degrees F (175 degrees C). Grease an 8-inch square baking dish.
Dissolve coffee in boiling water in a small bowl.
Melt chocolate in a microwave-safe glass or ceramic bowl in 30-second intervals, stirring after each melting, for 1 to 3 minutes.
Beat sugar and butter together in a bowl until light and fluffy. Beat melted chocolate chips, eggs, and and coffee mixture into sugar mixture.
Whisk flour and cinnamon together in a bowl. Gradually stir flour mixture into chocolate mixture until batter is combined. Pour batter into prepared baking dish.
Bake in the preheated oven until a toothpick inserted into the center comes out clean, 25 to 30 minutes. Cool on a wire rack before cutting into squares.
