TECHNOLOGY FOCUS - POLYMERS - Preparation (Claimed): Preparation of (I) comprises reacting n-times halogenated alkyl or aryl compound of formula (LXn) (II) and/or a silane compound of formula (Si(LXn-1)4) (III) with at least a silane compound of formula (SiX14) (IV) in the presence of metal organic compound.X = halo;X1 = halo or alkoxy; andn = 2-6.Preferred Process: The process comprises reacting (III) with a metal organic compound to obtain a silicon-metal compound of formula (Si(LMn-1)4), subsequently adding (IV) and further crosslinking. In the process, in addition to or in place of (II) and (III), at least a compound of formula (L1X1), Si(L1)2(LX1n-1)2 or Si(L1)(LX1n-1)3, at least a compound, preferably a boron containing compound of formula (BX13), (B(LX1n-1)3), or (B(L1)(LX1n-1)2), a germanium containing compound of formula (Ge(LXn-1)3) or (Ge(L1)(LX1n-2)2), a tin containing compound of formula (Sn(LXn-2)3), (Sn(L1)(LX1n-1)2), a nitrogen containing compound of formula (N(LX1n-1)3), (N(L1)(LX1n-1)2) or a phosphorus containing compound of formula (P(LX1n-1)3). (II) is two times halogenated. The process takes place in the presence of a solvent, preferably an ether having a melting point of less than 0 degrees C.M = metal; andL1 = acyclic or cyclic 5-50C-alkyl or 5-50C-aryl (both optionally substituted), preferably CH3, C2H5, n-propyl, isopropyl, n-butyl, isobutyl or tert.butyl, where L1 do not permit bonding with further structural units.Preferred Components: (L) is bonded with at least a further structural unit containing L and silicon atom, where the structural unit is of formula (L1Si(L-)3) or ((L1)2Si(L-)2), preferably substituted silicon unit of formula (i)-(iv). (I) exhibits: a specific Brunauer-Emmett-Teller surface of 500-3000, preferably 700-2000 m2 g-1; an average pore size of less than 2 nm, preferably greater than 0.1 nm; and a micropore volume of 0.2-1.5, preferably 0.3-0.5 cm3 g-1.B1 = B, N, Ge, Sn or P. Preferred Definitions:    L = phenyl group of formula (a), bicyclo(4.2.0)octa-1,3,5-triene group of formula (b), naphthalene group of formula (c) or (d), biphenyl group of formula (e), 4,5,9,10-tetrahydro-pyrene group of formula (f), pyrene group of formula (g), (1,1',4',1'')terphenyl group of formula (h), substituted benzene group of formula (i) or (j), pyridine group of formula (k) or (l), pyrimidine group of formula (m) or (n), quinoline group of formula (o), (2,2')bipyridinyl group of formula (p), (2,2')bipyrimidinyl group of formula (q), (1,10)phenanthroline group of formula (r), substituted bicyclo(3.3.1)nonane group of formula (s) or (t), trityl benzene group of formula (u) or (v); and    X = H, halo, optionally substituted alkyl, alkenyl, alkynyl or alkoxy.    EXAMPLE - Tetrakis(4-bromophenylsilane) (0.5 g) was dissolved in dry tetrahydrofuran (50 ml) under argon atmosphere. The mixture was cooled at -10 degrees C in an ice water bath and n-butyl lithium (1.23 ml) was dropwisely added. After 10 minutes of stirring at -10 degrees C, tetraethylorthosilicate (0.17 ml) was dropwisely added and stirred. Further distilled water (40 ml) was added. The obtained precipitation was centrifuged and washed twice with tetrahydrofuran, water and ethanol. The obtained mixture was dried at 100 degrees C and for at least 6 hours to obtain corresponding poly(1,4-phenylene)silane (83%) with a specific Brunauer-Emmett-Teller surface of 780 m2 g-1.