Some properties of unsaturated hydrocarbons have been investigated wit
h topological methods in this study. Fifteen physico-chemical properti
es of alkenes, alkynes and alkyl benzenes are correlated with topologi
cal indices and a general empirical equation is proposed as follows: P
-t = AN(a) + BXvb + CIxc + D. Regression analyses have given the calcu
lated results. It is found the fifteen physico-chemical properties of
the unsaturated hydrocarbons have excellent correlativity with the top
ological indices.