Synthesis and Properties of 1,8‐Di(2‐thienyl)‐, 1,8‐Bis(5,2′‐ bithiophene‐2‐yl)‐, 1,8‐Bis(5,2′:5′,2′′‐terthiophene‐2‐yl)‐, and 1,8‐ Bis(5,2′:5′,2′′:5′′,2′′′‐quaterthiophene‐2‐yl)naphthalenes and Related Compounds.