Is it possible to have active low window comparator using open collector output opamps?
Open collector opamps don't exist as an opamp needs to have an output that can be driven low or high.
Open collector comparators do exist, the LM393 is a popular example.


As mentioned in the comments, with open collectors outputs and diodes you can only make an OR function. We can still use something similar as can be seen in the schematic that I made:







simulate this circuit &ndash; Schematic created using CircuitLab

Note that I have drawn the open collector comparator explicitly as a comparator with an NPN. That is similar to what is inside for example the LM393. So Comp1 and Q1 would be on the same chip.

Now the output signal will be high when Vin is within the window.

Just add an inverter and you will get a signal that is low when Vin is inside the window.