The solidus and liquidus in the binary system Zr-Al, in the composition range 20-94.6 at.% Zr at 1573-2133 K were measured by using a thermo-optometric technique viz., the spot technique for the first time. The maximum uncertainty in the composition measured by gravimetry was +/- 1 at.% Zr. The experimental values are in good agreement with a recent thermodynamic assessment of this binary system. The uncertainties in the measured values of the temperatures pertaining to the invariant equilibria, L <-> ZrAl3, L <-> ZrAl2 + ZrAl3, L + ZrAl2 <-> Zr2Al3 and L + Zr3Al4 <-> Zr3Al2 are within 5 K. All these measurements have been done in homemade Y2O3 crucibles. Chemical compatibility of alloys (65 at.% Zr) with Y2O3 crucible had also been examined by using a Scanning Electron Microscope (SEM) along with Energy Dispersive X-ray Analysis (EDAX). Our study indicates that Y2O3 crucibles are compatible with Al-65 at.% Zr alloy.