Synthesis and Structural Study of 4H ‐Cyclopenta[ c ]thiophene‐5,5( 6H )‐dicarbonitrile and 6,6‐Dimethyl‐1,4‐dihydro‐ 5H ‐cyclopenta[ d ][1,2]dithiine‐5,7( 6H )‐dione

Two sulfur annulated fused heterocycles, 4H ‐cyclopenta[ c ]thiophene‐5,5( 6H )‐dicarbonitrile ( 1 ) and 6,6‐dimethyl‐1,4‐dihydro‐ 5H ‐cyclopenta[ d ][1,2]dithiine‐5,7( 6H )‐dione ( 2 ) were synthesized and characterized using NMR, FT‐IR and SCXRD. Their synthetic approaches were different and opposite from each other. In 1 the fused bicyclic system obtained starting from the heterocycle and extend to the alicyclic unit, whereas synthesis of 2 was started from alicyclic unit to end up getting heterocyclic dithiine unit. Optical and electrochemical properties of 1 and 2 were explored. Both the molecules are highly crystalline due to the presence of strong intermolecular interaction including C‐H … N and C‐H … S for 1 or C‐H … O and C‐H … S for 2 .