Substituent effects in chain and ring π-systems studied by core-electron binding energies calculated by density functional theory

► Core electron binding energy shifts (ΔCEBE) of carbons in 1-X-hexatrienes are close to those in Ph-X. ► ΔCEBE in 1-X-hexatrienes correlate linearly with the Hammett σ substituent constants. ► The substituent effect is similar between 1-X-hexatriyne and 1-X-hexatriene. ► Average ΔCEBE of the five carbon atoms between C2 and C6 in 1-X-hexatriyne were calculated.