TECHNOLOGY FOCUS - POLYMERS - Preferred Capacitor: The second layer is a conductive polymer layer made from pyrrole, aniline or their derivative by chemical polymerization, linking onto which is a conductive polymer produced by electrolytic polymerization, or on which is formed a third polymer layer of thiophene or its derivative by chemical polymerization. On the third layer, a conductive polymer layer is formed and is fixed by electrolytic polymerization. The conductive polymer produced by electrolytic polymerization can be a polymer of thiophene, pyrrole, aniline or their derivative.A fourth conductive polymer may be formed by chemical polymerization between the electrolytically polymerized conductive layer and the carbon layer, which can be obtained from thiophene, pyrrole, aniline or their derivative. The fourth layer may contain 1-50 wt.% a conductive powder such as carbon powder, or the conductive polymer powder.Preferred Process: The first and/or third layers are formed by heating a solution of a water-containing polymeric thiophene or its derivative in a solvent after coating onto the anode body by impregnation, or by chemical polymerization of thiophene or its derivative as a mixture of the monomer, dopant and oxidant after impregnating the anode body. The second layer is similarly prepared from a monomer of pyrrole, aniline or their derivative as its mixture with a dopant and oxidant, or from a mixture of the monomer and an oxidative dopant, or by impregnating the anode body with the monomer first before mixing with a solution of the oxidant and dopant or oxidative dopant prior to polymerization, or by impregnating with the monomer and dopant solution first then with monomer and oxidant mixture.On the fourth electrolytically polymerized layer, a fifth chemically polymerized conductive polymer layer may be added and then a carbon layer is formed on top. Such fifth layer particularly contains 1-50 wt.% a conductive powder which can be carbon powder or the conductive polymer powder, which can be produced from thiophene, pyrrole, aniline or their derivative as defined above.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Materials: The thiophene derivative is particularly one with the 3-position, 3- and 4-positions, or S-position of the thiophene skeleton substituted with hydroxyl, acetyl, carboxyl, alkyl, or/and alkoxy, or 3,4-alkylenedioxythiophene. Preferably, the pyrrole derivative is on with the 3-position, 3- and 4-positions, or N-position of the pyrrole skeleton substituted with 1 or more of hydroxyl, acetyl, carboxyl, alkyl and alkoxy, while the aniline derivative is one in which the aniline skeleton is substituted by at least 1 chosen from alkyl, phenyl, alkoxy, ester and thioether. EXAMPLE - An angular tantalum sintered body (3 x 4 x 1.5 mm) was anodically oxidized in aqueous 0.05 wt.% phosphoric acid at 20 V and rinsed to give a dielectric oxide layer on which conductive polymer layers (31, 32 and 34, respectively) were formed from 5 wt.% ethylenedioxythiophene, 25 wt.% ferric p-toluenesulfonate, 30 wt.% n-butanol, 37 wt.% isopropanol and 3 wt.% water; from 48 wt.% pyrrole, 32 wt.% ethanol and 20 wt.% water then 5 wt.% ammonium persulfate and 3 wt.% p-toluenesulfonic acid in 93 wt.% water, both after impregnation by chemical polymerization; as well as from 0.3 M pyrrole and 0.1 M-sodium naphthalene sulfonate in water by electrolytic polymerization after applying electrodes to the above layers (31 and 32). On layer (34), a layer of carbon then a layer of silver was coated on prior to bonding with a cathode terminal plate using a conductive adhesive, linking with the anode lead and anode terminal plate, and packing in a resin casing to give a solid electrolytic capacitor with a specification of voltage at 6.3 V and capacitance of 150 microfarads.    Results of the evaluation study were: capacitance ratio = 100/99% (before and after test, respectively); current leakage = 3.1/3.2 microamps; and impedance = 40/45 milliohms.