Polymers with silicon-silicon connections in main chain have different properties from conventional silicone polymer (Dimethylpolysiloxane) or carbon polymer. Our laboratory has mainly investigated and created σ-π-conjugated polymers with good properties of organic silicone polymers repeating silicon-silicon connections and π-electron system units. For example, polymers with repeating silicon units and thiophene unit are noted. These polymers are useful as conjugated molecules and can be applied as electroluminescence device material or opt-electrotransforming materials. These polymers have flexible main chains, high solubility in organic solvents, and easy forming of films as conjugated polymers.