SINESTRO
-ALL of Siestros specials are punishable by Soul Crush, Singularity and F222 on block provided your in range for each respective punish.
-while in Demon Mode both Impact Event (boulder) and Final Shackles are punishable on block by Event Horizon from full screen. But you need to be on point when punishing the Shackles because the timing is tight and It needs to be a frame perfect reversal. BTW this is a pain in the ass to pull off consistently online. With Impact Event though you have a little more time to work with. Great for closing the distance.
DEALING WITH FULL SCREEN SINESTRO BOULDERS
-when your all out of trait you can use MB3 on reaction to Impact Event to absorb the hit then dash forward and punish him with soul crush. Keep in mind that you WILL STILL TAKE FULL DAMAGE from the Boulder. Point of this is not to avoid the 8% damage. The point is to get in and to punish him for just throwing boulders out recklessly.
-after the Soul Crush you have enough time for one or maybe two dashes to get to where Raven wants to be. You can choose to burn another bar for an additional soul crush if you want to get a little extra DMG and maybe better positioning.
Keep in mind that pulling this off in a match where the Sinestro player is bombarding you with Projectiles and Shackles is kind of tough to say the least and online is another story altogether but at least it's another option. Luckily Sinestros animation before summoning the boulder is pretty long and recognizable.
BTW I know I'm using the Reversal Mode to get him to throw the Boulders but I promise I'm doing it on reaction to the animation. Try it. It's not that hard.
Also I personally use f3 because its MUCH easier for me but using b3 is still possible.