Poly(p-phenylenevinylene) and its derivatives (DP-PPV and labeled R-7) were carefully studied using x-ray photoelectron spectroscopy. The C 1s peaks taken from spin-coated thin films of these materials were fitted with the consideration of the bonding state differences (-C=CH and C=C-,etc). The intensity of these C Is peaks agrees well with the value estimated from the bonding state consideration. (C) 1997 American Institute of Physics.