Abstract The static secondary ion mass spectroscopic (SIMS) spectra of some environmentally stable substituted derivatives of polyacetylene, such as poly(phenylacetylene), poly(1-phenyl-1-propyne), poly(1-chloro-2-phenylacetylene), poly(( o-trimethylsilyl)-phenyl)-acetylene) and poly(t-butylacetylene), have been examined. Structural differences among the polymers are reflected in the spectra and are compared with previous work on the partially unsaturated aliphatic polymers. The presence of strongly ionic elements such as Si and Cl in the polymer structure alters the ionization of fragments. The static SIMS spectra are also compared with those of polystyrene which has a saturated hydrocarbon backbone. An attempt is made to account for the effect of chain conjugation and substituents on the various polymer spectra.