The synthesis of mostly new acetylenes, R1CCR2, (R1 = 4‐t‐butylphenyl; R2 = 4‐t‐butylphenyl; 4‐[(t‐butyl)(diphenyl)silyloxy]phenyl; 1‐naphthyl; 2‐naphthyl; 9‐anthryl) is reported. Their UV‐vis characteristics are discussed in comparison to the results of TD‐DFT calculations. R1CCR2 (except for R2 = 9‐anthryl) give polyacetylenic polymers—[C(R1) = C(R2)]‐n, insoluble if R1 = R2 and well soluble if R1 ≠ R2 in polymerization with TaCl5/SnBu4. Polymerizability increases with increasing monomer triple bond accessibility for the catalyst. The photoluminescence yield of the soluble polymers rises in the R2 order: 1‐naphthyl < 2‐naphthyl < 4‐[(t‐butyl)(diphenyl)silyloxy]phenyl.