A new way of preparing thin films of phthalocyanines (PC) is demonstra
ted. Starting from the precursor isoindoline 2, a solid-state synthesi
s of Mn and Zn PC 3a and 3b in thin films by a thermoreaction is descr
ibed. The optical properties of the thin films which absorb strongly i
n the near infrared are investigated. Parameters such as film thicknes
s, optical spectra, film composition and PC 3 yield are measured and c
alculated using optical and mechanical methods. The data also indicate
that the conversion of isoindoline 2 into PC 3 is very efficient.