Abstract: A color coded molecular model assembly kit is provided for representing organic molecular structures and shapes comprising two basic and complementary construction units capable of being interlocked. The first basic construction units are color coded plastic tubes of three different lengths such that when coupled to two of said second basic construction units the distances between the centers of the coupling means represent 1.36 Angstroms, 1.54 Angstroms and 1.81 Angstroms respectively and represent the bonds between adjacent atoms. The second basic construction units are color coded coupling means for said tubes according to the valency of the atoms to be joined, the center of said coupling means representing atom conters, said coupling means having radial arms substantially located on the surface of a sphere with the center of the coupling unit being the center of the sphere.