Door closing system for opening and closing a door lock in a door, - wherein the door closing system comprises a first door handle unit with a first door handle and a second door handle unit with a second door handle, - wherein the first door handle and the second door handle are pivotable about a common pivot axis, - wherein the door closing system comprises a coupling device with an axially aligned polygonal pin, which has a first pin piece and a second pin piece, - wherein the first pin piece is connected to the first door handle in a non-rotatable manner and the second pin piece is connected to the second door handle in a non-rotatable manner, - wherein the pin pieces (11a, 11b) of the polygonal pin are separated from one another and only the first pin piece of the polygonal pin can be coupled to the door lock, - wherein the coupling device comprises an axially aligned coupling pin which is arranged in the polygonal pin and can be shifted axially into a coupling position and into a decoupling position, and - wherein the pin pieces (11a, 11b) of the polygonal pin are connected to one another in a non-rotatable manner in the coupling position of the coupling pin and can be pivoted relative to one another in the decoupling position of the coupling pin, - wherein the coupling pin has a rotational area and a rotationally asymmetrical coupling area axially adjacent thereto, and - wherein for the coupling area, a first mating contour is formed in the first pin piece and a second mating contour is formed in the second pin piece, so that when the coupling area engages with the respective mating contour (14a, 14b) the coupling pin and the respective pin piece (11a, 11b) can be connected to one another in a non-rotatable manner, characterised in that - the coupling pin and the first pin piece can be pivotably connected to one another over the rotatational area, and - in the coupling position the coupling pin is displaced axially towards the first door handle, so that the coupling area is received in the first mating contour and in the second mating contour, and - in the decoupling position the coupling pin is displaced axially towards the second door handle, so that the coupling area is only in positive engagement with the second mating contour and the rotational area of the coupling pin is arranged in certain sections in the mating contour. - wherein the door closing system comprises a first door handle unit with a first door handle and a second door handle unit with a second door handle, - wherein the first door handle and the second door handle are pivotable about a common pivot axis, - wherein the door closing system comprises a coupling device with an axially aligned polygonal pin, which has a first pin piece and a second pin piece, - wherein the first pin piece is connected to the first door handle in a non-rotatable manner and the second pin piece is connected to the second door handle in a non-rotatable manner, - wherein the pin pieces (11a, 11b) of the polygonal pin are separated from one another and only the first pin piece of the polygonal pin can be coupled to the door lock, - wherein the coupling device comprises an axially aligned coupling pin which is arranged in the polygonal pin and can be shifted axially into a coupling position and into a decoupling position, and - wherein the pin pieces (11a, 11b) of the polygonal pin are connected to one another in a non-rotatable manner in the coupling position of the coupling pin and can be pivoted relative to one another in the decoupling position of the coupling pin, - wherein the coupling pin has a rotational area and a rotationally asymmetrical coupling area axially adjacent thereto, and - wherein for the coupling area, a first mating contour is formed in the first pin piece and - the coupling pin and the first pin piece can be pivotably connected to one another over the rotatational area, and - in the coupling position the coupling pin is displaced axially towards the first door handle, so that the coupling area is received in the first mating contour and in the second mating contour, and - in the decoupling position the coupling pin is displaced axially towards the second door handle, so that the coupling area is only in positive engagement with the second mating contour and the rotational area of the coupling pin is arranged in certain sections in the mating contour.