The reactions of 1,2-dithiole-3-thiones and 1,2,4-dithiazole-3-thiones with acetylenic esters provide initial 1,3-dithiole products by 1,3-dipolar additions. 3-Imino-1,2-dithioles react similarly to form thiazoles. Both these initial adducts react further with more acetylenic ester to form spiran type structures. The stereochemistry of these is discussed briefly and applied to their reactivity and spectroscopic properties.