Is it possible to record screens of two android phones connected to a PC?

Execute adb help and notice

-s

  - directs command to the device or emulator with the given


serial number or qualifier. Overrides ANDROID_SERIAL


environment variable.

Serial number can be found from adb devices. For example,

bash-4.X# adb devices

List of devices attached 

543b45da

  device

543b45da (imaginary here) is the serial number for my device.

Serial number can also be found in the output of adb shell getprop or the file build.prop under /system. Look for the term(s) ro.boot.serialno or ro.serialno.

Now that you've the serial number, simply do

adb -s SERIAL_NUMBER YOUR_COMMAND/ADB_ARGUMENT

E.g.

adb -s 543b45da shell getprop

You can execute command(s) for multiple devices from multiple terminals simultaneously. The answer by moonbutt74 may also help.